Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

The inclusion complexations of paracyclophane (CP44) and beta-cyclodextrin (beta-CD) with several anilinonaphthalene sulfonic acids (ANSs) have been characterized via the enhancement of fluorescence spectra upon inclusion. beta-CD and CP44 formed 1:1 inclusion complexes with ANSs, and the high stability of inclusion complexes of the latter was demonstrated. The thermodynamic parameters observed from the temperature dependence of the inclusion constants (van't Hoff analysis) showed that CP44 inclusion complexations with ANSs are enthalpy-driven. Furthermore, the structure of the inclusion complexes was discussed based on H-1- and 2D ROESY-NMR measurements. It was found that CP44 encapsulates the naphthalene moiety of ANSs. On the other hand, differences in the structures of the beta-CD inclusion complexes were observed for the 4-OH-substituted ANS. The molecular recognition for the inclusion of beta-CD was found to be sensitive compared with that of CP44. In addition, the local polarity inside the CP44 and beta-CD cavities was evaluated using ANSs as the fluorescence probe. Based on these results, we have suggested that the local polarity of ANSs in the hydrophobic cavities of CP44 and beta-CD plays an important role in quantum yield enhancement upon inclusion.

DOI： 10.1007/s10847-018-0790-4

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The inclusion complexation of aromatic amines with cucurbit[6]uril (CB[6]) capped with alkali metal cations was studied spectrophotometrically. We showed that CB[6] capped with alkali metal cations forms a 1:1 inclusion complex with the aromatic amine guests (neutral organic molecules), independent of the length of guest molecules. The effects of salts on the inclusion constants of CB[6] in the presence of different alkali salts were examined and it was found that the inclusion constants increased in the order of alkali cation Cs+ < Na+ < K+, suggesting the interaction of amine guests with the capped alkali metal cation. Further, the structures of the inclusion complexation of aromatic amines with CB[6] were characterized by H-1 NMR measurements. Based on the results, the inclusion abilities of CB[6] capped with alkali metal cations are discussed.

DOI： 10.1007/s10847-017-0727-3

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WALTER DE GRUYTER GMBH  

Using the inclusion complexation of methylene blue with p-sulfonatocalix[ 6] arene (Calix-S6) as a chemical indicator, the association constants of inclusion complexes of Calix-S6 with visible-spectroscopically inert 1-butyl-3-methylimidazolium salts (ionic liquids (IL): counter anions BF4-, PF6-, and Cl-) were determined. It was found that the experimentally observed association constants of IL with Calix-S6 in a water-methanol mixture increased in the order of counter anion Cl- < BF4- < PF6-. The F-19 NMR signals of counter anions BF4- and PF6- shift upfield upon addition of Calix-S6. From the F-19 NMR chemical shifts, we suggested that Calix-S6 forms weak 1 : 1 complexes with the BF4- and PF6- anions. The binding constants and their thermodynamic parameters for the complexation of the BF4- and PF6- anions with Calix-S6 were evaluated in a water-methanol mixture (6 : 4 (V/V)) at 298 K:K-A = 26.2M (-1) for BF4- and 106 M-1 for PF6 (-). Based on the results, the characteristics for the complexation of the counter anions with Calix-S6 were discussed and the inclusion constants of Calix-S6 with the cationic ringmoiety of 1-butyl-3-methyl-imidazolium salts were determined.

DOI： 10.1515/zpch-2015-0611

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Using the inclusion complexation of methylene blue as a chemical indicator, the inclusion constants of imidazolium and pyrrolidinium chlorides (ionic liquids (IL)) with p-sulfonatocalix[6]arene (Calix-S6) were determined in a water-methanol mixture. In the inclusion of imidazolium chlorides, we found the characteristic inclusion constants, dependent on the length of the alkyl side chain. From the temperature effect on the inclusion, the differences in the inclusion interactions of imidazolium and pyrrolidinium ring moiety with the sulfonate groups of the Calix-S6's portal were observed. Further, from high-pressure studies on the inclusion complexation, the volume changes caused by the conformational changes of Calix-S6 and desolvation around the guest and host molecules upon inclusion were evaluated. Based on the results, we demonstrated that the volume change related to desolvation upon inclusion plays an important role in the reaction volume for the inclusion equilibrium of IL with Calix-S6. The structures of the inclusion complexes were established from 2D ROESY NMR measurements and a volumetric study of the inclusion complexation with p-sulfonated Calix-S6 having a flexible cavity was performed.

DOI： 10.1007/s10847-016-0660-x

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Using unique guest probes having more than one bulky group, we demonstrate substituent dependence on group inclusion for the molecular recognition of beta-cyclodextrins (beta-CDs). Group-inclusion equilibrium with 6-O-alpha-D-glucosyl-b-cyclodextrin (G-beta-CD) having a bulky glucosyl side chain has been shown to be significantly altered as compared with unmodified beta-CD. We suggest that the bulky substituents in guest and host molecules play an important role for the group inclusion of molecular recognition.

DOI： 10.1007/s10847-015-0537-4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

By synthesizing unique nitroxide probes (alpha-substituted phenyl-2,4,6-trimethoxybenzyl(t-butyl) nitroxide), we have shown that p-sulfonatocalix[8]arene (Calix-S8) and gamma-cyclodextin (gamma-CD) form electron spin resonance spectroscopically separable group-inclusion complexes (alpha-substituted phenyl-in (R-in) and t-butyl-in complexes) and determined the group-inclusion constants of Calix-S8 and gamma-CD. Using nitroxide probes, we have examined the effects of substituent and external pressure on group-inclusion complexation with Calix-S8 and gamma-CD. Experiments on pressure dependence enabled us to calculate the reaction volume (Delta V) for R-in and t-butyl-in complex formations. Delta V for group-in complexation with Calix-S8 had negative values. In contrast, Delta V values for gamma-CD showed positive values, which is responsible for the repelled water molecules in the CD cavity. The characteristic pressure effects on group-in complexation suggest that group recognition by gamma-CD is sensitive when compared with that by Calix-S8.

DOI： 10.1080/08957959.2014.947605

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The key precursor, N-2-(N,N -dimethylaminomethylene)-6-hydroxymethyl-8-methyl-3-[2-(4-nitrophenyl)ethyl]-7-xanthopterin (16) was efficiently prepared from 2,5-diamino-6-methylamino-3H-pyrimidin-4-one (5) and ethyl 3-(tert-butyldimethylsilyloxy)-2-oxopropionate (12), followed by the protection of the pteridine ring. Glycosylation of 16 with 1-O-acetyl-2,3,5-tri-O-benzoyl-beta-D-ribofuranose (18) in the presence of tin(IV) chloride yielded the corresponding beta-D-ribofuranoside. Successive removal of the protecting groups of the resulting D-ribofuranoside provided asperopterin A (4b).

DOI： 10.1515/pterid-2013-0005

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Starting with N-acetyl-D-glucosamine, methyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-beta-D-xylo-hexofuranosid-5-ulose (18) was prepared in 7 steps. The addition reaction of dimethyl phosphonate to 18, followed by deoxygenation of its 5-hydroxy group, provided the 5-deoxy-5-dimethoxyphosphoryl-D-glucofuranoside derivative (21a). The hydride reduction of 21a, followed by the action of hydrochloric acid and then hydrogen peroxide, afforded the first D-glucosamine analog (23) having a phosphoryl group in the hemiacetal ring. This was converted into the per-O-acetylated N-acetyl-D-glucosamine phospha-sugar (25), while the same treatment of the 5-deoxy-5-dimethoxyphosphoryl-L-idose dimethyl acetal derivative (13b) afforded the N-acetyl-L-idosamine phospha-sugar (29).

DOI： 10.3987/COM-12-S(N)69

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Some pterins having various kind of sugars attached to the hydroxyalkyl side-chain at C-6 are known to occur in certain prokaryotes as exemplified by 2'-O-(alpha-D-glucopyranosyl)biopterin isolated from various kinds of cyanobacteria. A synthetic exploration of various types of glycosides of biopterin and related pterins has been undertaken owing to a marked interest in their physiological functions and biological activities as well as the structural proof of those natural products. This review summarizes our synthetic studies on natural pterin glycosides by employing the appropriately protected N-2-(N,N-dimethylaminomethylene)-3-[2-(4-nitrophenyl)ethyl]pterin derivatives as glycosyl accepters.

DOI： 10.3987/REV-12-742

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The key precursor, N-2-(N,N-dimethylaminomethylene)-6-hydroxymethy1-8-methyl-3[2-(4-nitrophenypethyl]-7-xanthopterin (9) was efficiently prepared from 2,5-diamino-6-methylam1no-3H-pyrimidin-4-one (3) and ethyl 3-(tert-butyldimethylsilyloxy)-2-oxopropionate (11). The first synthesis of asperopterin-A (2b) was achieved by treatment of 9 with 1-O-acetyl-2,3,5-tri-O-benzoy1-beta-D-ribofuranose (15) in the presence of tin(IV) chloride, followed by removal of the protecting groups.

DOI： 10.3987/COM-11-S(P)57

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N-Benzyloxy-2-(diethoxyphosphoryl)pent-4-enamide (6) was prepared from ethyl diethoxyphosphorylacetate in a 3-step sequence. Oxidative cleavage of the terminal olefin of 6 with osmium tetroxide and sodium periodate afforded 1-benzyloxy-3-diethoxyphosphoryl-5-hydroxy-2-pyrrolidone (7). The first synthesis of racemic SF-2312 was achieved by treatment of 7 with trimethylsilyl bromide, followed by hydrogenolysis.

DOI： 10.3987/COM-10-S(E)80

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1',2'-Di-O-acetyl-N(2)-(N,N-dimethylaminomethylene)-3-[2-(4-nitrophenyl) ethyl] neopterin (1) was prepared from neopterin in 5 steps. Glycosylation of 1 with methyl 2,3,4-tri-O-benzoyl-alpha-D-glucopyranosyluronate bromide in the presence of silver triflate and tetramethylurea afforded the corresponding 3'-O-(methyl beta-D-glucopyranosyluronate) neopterin derivative (2) in 64% yield. The first synthesis of 3'-O-(beta-D-glucopyranosyluronic acid) neopterin was achieved by successive removal (4 steps) of the protecting groups of 2.

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The key precursor, N(2)-(N,N-dimethylaminomethylene)-6-hydroxymethyl-3-[2-(4-nitrophenyl)ethyl]pterin (11) was efficiently prepared from 2,5,6-triamino-4-hydroxypyrimidine (8) in 5 steps. The first, unequivocal synthesis of 6-hydroxymethylpterin alpha-D-glucoside (6a) was achieved by treatment of 11 with 4,6-di-O-acetyl-2,3-di-O-(4-methoxybenzyl)-alpha-D-glucopyranosyl bromide (16) in the presence of tetraethylammonium bromide and N-ethyldiisopropylamine, followed by removal of the protecting groups, while 6-hydroxymethylpterin beta-D-glucoside (6b) was prepared by means of selective glycosylation of 11 with 2,3,4,6-tetra-O-benzoyl-alpha-D-glucopyranosyl bromide (12) in the presence of silver triflate and tetramethylurea.

DOI： 10.3987/COM-09-S(S)78

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A novel glycosyl donor, 4,6-di-O-acetyl-2,3-di-O-(4-methoxybenzyl)-alpha-D-glucopyranosy bromide (15) was efficiently prepared from D-glucose in 8 steps. The first synthesis of 2'-O-(alpha-D-glucopyranosyl)biopterin (2) was achieved by treatment of the key precursor, N(2)-(N,N-dimethylaminomethylene)-1'-O-(4-methoxybenzyl)-3-[2-(4-nitrophenyl)ethyl]biopterin (6) with 15 in the presence of silver triflate and tetramethylurea, followed by removal of the protecting groups.

DOI： 10.3987/COM-08-S(F)60

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Glycosylation of N(2)-(N, N-dimethylaminomethylene)-1'-O-(4-methoxybenzyl)-3-[2-(4-nitrophenyl) ethyl] biopterin (14) with the novel donor 4,6-di-O-acetyl-2,3-di-O-(4-methoxy-benzyl)-alpha-D- -glucopyranosyl bromide (19) in the presence of silver triflate and tetramethylurea predominantly afforded the corresponding a-D-glucopyranoside (20a), from which 2'-O-(alpha-D-glucopyranosyl) biopterin (1) was obtained by the successive removal of the protecting groups.

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The equilibrium constants (K) for the inclusion complexation of three kinds of beta-cyclodextrins (beta-CDs: native beta-CD, heptakis(2,6-di-O-methyl)-beta-CD, and 6-O-alpha-d-glucosyl-beta-CD) with OH-substituted naphthalenes (2-naphthol, 2,3-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene) were determined from the induced chemical shifts of NMR measurements for inclusion complexes: K = 188-1,250 mol(-1) dm(3). The modified beta-CDs form stable 1:1 inclusion complexes with OH-substituted naphthalenes, and the high stability of inclusion complexes of 2,6-dihydroxynaphthalene having a hydrophobic body and hydrophilic ends is shown. In addition, the structures of inclusion complexes were characterized by 2D ROESY NMR measurements. The differences in the structure of the inclusion complexes were observed for three kinds of naphthol guest molecules. Based on the results, the inclusion abilities enhanced by methylation of the OH groups at the CD rim or the side chain of branched beta-CD are discussed.

DOI： 10.1007/s10847-009-9545-6

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L-Rhamnose was led, in a 14-step-sequence, to N(2)-(N,N-dimethylaminomethylene)-1'-O-(4-methoxybenzyl)-3-[2-(4-nitrophenyl)ethyl]biopterin (23), an appropriately protected precursor for 2'-O-glycosylation, while 4,6-di-O-acetyl-2,3-di-O-(4-methoxybenzyl)-alpha-D-glucopyranosyl bromide (32), a novel glycosyl donor, was efficiently prepared from D-glucose in 8 steps. The first synthesis of 2'-O-(alpha-D-glucopyranosyl)biopterin (2a) was achieved by treatment of the key intermediate 23 with 32 in the presence of silver triflate and tetramethylurea, followed by successive removal of the protecting groups. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2009.07.043

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The key precursor, N(2)-(N,N-dimethylaminomethylene)-l'-O-(4-methoxybenzyl)-3-[2-(4-nitrophenyl)ethyl]ciliapterin (15) was efficiently prepared from D-xylose via an improved route. The first synthesis of 2'-O-(alpha-D-mannopyranosyl)ciliapterin (2c) was achieved by treatment of 15 with 2,3,4,6-tetra-O-benzoyl-alpha-D-mannnopyranosyl bromide in the presence of silver triflate and tetramethylurea, followed by removal of the protecting groups.

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The key, versatile precursors N-2-(N,N-dimethylaminomethylene)-1'-O-(4-methoxybenzyl)-3-[2-(4-nitrophenyl)ethyl]biopterin (29a) and its ciliapterin analog (29b) were prepared, respectively, from D-xylose (in 14 steps) and L-xylose (in 11 steps). Treatment of 29a and 29b with 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-beta-D-glucopyranosyl bromide in the presence of silver triflate and tetramethylurea, followed by removal of the protecting groups, led to the first selective syntheses of limipterin (3) and tepidopterin (5), respectively. (c) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2007.12.042

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N(2)-(N, N-Dimethylaminomethylene)-3-[2-(4-nitrophenyl) ethyl]-1',2'-di-O-(trimethylsilyl)biopterin (4) was prepared from biopterin (1a, 86% overall yield) in 5 steps. Glycosylation of 4 with 1,2,3,5-tetra-O-acetyl-beta-D-ribofuranose (5a) and its 2,3,5-tri-O-benzoyl analog (5b) respectively afforded the corresponding 2'-O-(2,3,5-tri-O-acetyland 2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl) biopterin derivatives (6a, 42% and 6b, 60%) as major products. Removal of the protecting groups of 6b provided 2'-O-(beta-D-ribofuranosyl)biopterin (1c, 87% overall yield) in 3 steps.

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N(2)-(N,N-Dimethylaminomethylene)-1'-O-(4-methoxybenzyl)-3-[2-(4-nitrophenyl)ethyl]-L-threo-biopterin (14) was prepared from L-xylose in an 11-step-sequence. The first synthesis of tepidopterin (3) was achieved by treatment of 14 with 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-beta-D-glucopyranosyl bromide in the presence of silver triflate and tetramethylurea, followed by removal of the protecting groups. (C) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carres.2007.06.017

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(R)-2-Tosyloxypropanal (4) was prepared from D-mannitol in a 7-step sequence (51% overall yield). Addition of dialkyl phosphonates to 4 in the presence of titanium isopropoxide and the subsequent treatment with DBU stereoselectively afforded, in one-pot, fosfomycin dimethyl (5a) and dibenzyl (5b) esters both in 58% isolated yield.

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Methyl 4-deoxy-4-dimethoxyphosphinoyl-2,3-O-isopropylidene-beta-D-ribopyranoside (12a) and methyl 2,4-dideoxy-4-dimethoxyphosphinoyl-beta-D-erythro-pentopyranoside (20) were efficiently prepared respectively from methyl 2,3-O-isopropylidene-beta-D-ribopyranoside (7a) and its 3,4-O-isopropylidene isomer (7b) in appreciably improved total yields compared with those via previously reported routes. Compounds (12a, 20) were led to D-ribofuranose and 2-deoxy-D-ribofuranose phospho sugars (4, 5).

DOI： 10.3987/COM-07-S(U)34

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The addition reaction of dimethyl phosphonate to (2R,4S)-4-(tertbutyldimethylsilyl)oxymethyl-2-methyl-1,3-dioxan-5-one (11a), followed by dehydroxylation, provided 1-O-(tert-butyldimethylsilyl)-3-deoxy-3-dimethoxyphosphinoyl-2,4-O-ethylidene-D-erythritol (13a). Elongation of carbon skeleton of the D-erythrose (14) derived from 13a and then acidic methanolysis gave a mixture of methyl 2,4-dideoxy-4-dimethoxyphosphinoyl-alpha,beta-D-erythropentopyranosides (7), which was led to 2-deoxy-D-ribofuranose phospho sugar (4) in an appreciably improved total yield compared with the procedures via previously reported route.

DOI： 10.3987/COM-06-S(K)28

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Selective bromination of sucrose, followed by acetalation with 2,2-dimethoxypropane in 1,4-dioxane in the presence of p-toluenesulfonic acid, afforded methyl 6-bromo-6-deoxy-1,3-O-isopropylidene-alpha-D-fructofuranoside (4). The first chemical synthesis of 6-thio-D-fructopyranose was accomplished from 4 through its 6-S-acetyl-6-thio derivative.

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N-2-(N,N-Dimethylaminomethylene)-3-[2-(4-nitrophenyl)ethyl]-1',2'-di-O-trimethylsilyl-L-biopterin (6) was prepared from L-biopterin in 5 steps. Glycosylation of 6 with 2,3,4,6-tetra-O-benzoyl-alpha-D-glucopyranosyl trichloroacetimidate (9) and 1,3,4,6-tetra-O-acetyl-2-phtalimido-beta-D-glucopyranose (10) respectively afforded the corresponding 2'-O-(beta-D-glucopyranosyl) derivatives (12b, 12c) as major products. Removal of protecting groups of 12c provided naturally occurring limipterin (2).

DOI： 10.3987/COM-05-S(T)28

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Treatment of 3,4-O-isopropylidene-L-threo-pentos-2-ulose (7) with 5,6-diamino-1,3-dimethyluracil (8) afforded 1,3-dimethyl-6-[(1R,2S)-1,2,3-trihydroxy-1,2-O-isopropylidenepropyl]lumazine (9a) and its 7-substituted isomer (9b). Deoxygenation of 3'-hydroxy groups of 9a,b was investigated in connection with a practical transformation of neopterin into biopterin.

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Treatment of 1,4-di-0-mesyl-2,3-di-O-methyl-L-threitol (8b) with phenylphosphine in the presence of sodium hydride in DMSO, followed by the action of hydrogen peroxide, afforded 3,4-dimethoxy-1-phenylphospholane 1-oxide (7), while the same treatment of 1,5-di-O-mesyl-2,3,4-tri-O-methyl-mesoxylitol (11b) provided 2,3,4-trimethoxy-1-phenylphosphorinane 1-oxide (14).

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：GEORG THIEME VERLAG KG  

L-Rhamnose was converted, over a 13-step-sequence, into 2'-O-acetyl-N-2-(N,N-dimethylaminomethylene)-1'-O-(4-methoxybenzyl)-3-[2-(4-nitrophenyl)ethyl]-L-biopterin, an appropriately protected precursor of 1'-O- and 2'-O-monoglycosyl-L-biopterin. Thus, the first selective synthesis of these L-biopterin glycosides was accomplished by treatment of the precursor with either DDQ or sodium methoxide, then with tetra-O-benzoyl-alpha-D-glucopyranosyl bromide in the presence of silver triflate and tetramethylurea, followed by removal of the remaining protecting groups.

DOI： 10.1055/s-2006-949620

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The inclusion complexation of 6-O-alpha-D-glucosyl-beta-cyclodextrin (G-beta-CD), in which the glucosyl side chain is introduced to beta-CD, with various kinds of phenols was studied spectrophotometrically at high pressures. The characteristic effects of substituent and pressure were found for the inclusion complexation of G-beta-CD. The association constants K for the G-beta-CD inclusion complexation increased with an increase in the bulkiness of the 4-substituent groups in phenols. As the external pressure increases, the inclusion constants for the G-beta-CD complexation increased and the reaction volumes were estimated to be -3.8 to -19.4 cm(3) mol(-1) from their pressure dependences. From analysis of the effect of pressure on the inclusion complexation with G-beta-CD, the number of water molecules included in the G-beta-CD cavity in water was estimated. The number of water molecules repelled from the CD cavity plays an important role in the change in volume upon inclusion. In addition, the structures of the inclusion complexes of G-beta-CD with phenols have been established by 1D and 2D NMR measurements. Based on the results, we suggested that the ability of the G-beta-CD inclusion complexation is enhanced by the interaction between guest molecules and the glucosyl side chain of G-beta-CD.

DOI： 10.1007/s10847-005-7368-7

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Ethyl 4-bromo-2,3-dimethoxybutyl(phenyl)phosphinate (10a) was prepared from 2,3-di-0-methyl-L-threitol (12) in five steps. Reduction of 10a with sodium dihydrobis(2-methoxyethoxy)aluminate, followed by the action of hydrogen peroxide, afforded 3,4-dimethoxy-1-phenylphospholane I-oxide (3), while the reaction of 10a with magnesium in boiling THF resulted in the formation of ethyl 2-methoxy-3-butenyl(phenyl)phosphinate (26).

DOI： 10.3987/COM-05-S(K)15

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Acetalation of sucrose with 2,2-dimethoxypropane in 1,4-dioxane in the presence of p-toluenesulfonic acid, followed by acetylation, afforded methyl 4,6-di-O-acetyl-1,3-O-isopropylidene-alpha-D-fructofuranoside and 4-O-acetyl-2,3:5,6-di-O-isopropylidene-D-glucose dimethyl acetal as major products, while tosylation of the intermediate acetals provided methyl 6-O-tosyl-1,3-O-isopropytidene-alpha-D-fructofuranose. (C) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carres.2005.07.023

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS LTD  

The effects of pressure were examined for the inclusion complexation of water-soluble p-sulfonated calix[n]arenes (Calix-Sn: n = 4, Calix-S4; n = 6, Calix-S6; n = 8, Calix-S8) with methylene blue (MB). A differential pressure effect was found in the inclusion equilibria of Calix-Sn. As the external pressure increases, the inclusion equilibrium of MB with Calix-S4 and Calix-S6 shifts to the dissociation side. However, with Calix-S8, the inclusion equilibrium shifts to the association side with increased pressure. From the pressure dependence of the inclusion equilibria of Calix-Sn, the reaction volumes, which are changes in volume accompanied by inclusion, were estimated as 32.1 cm(3) mol(-1) for Calix-S4, 30.1 cm(3) mol(-1) for Calix-S6 and -13.8 cm(3) mol(-1) for Calix-S8. In addition, the structures of the inclusion complexes of Calix-Sn with MB have been established by H-1 NMR measurements. Based on the results, the behavior of inclusion complexation with Calix-Sn is discussed. Copyright (c) 2004 John Wiley T Sons, Ltd.

DOI： 10.1002/poc.888

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

3,4-Di-O-benzyl-6-deoxy-6-diethoxyphosphinyl-1,2-O-isopropylidene-beta-D-fructofuranose (13) was prepared from the known 1,2-O-isopropylidene-6-O-tosyl-beta-D-fructofuranose in five steps. Reduction of 13 with sodium dihydrobis(2-methoxyethoxy)aluminate, followed by the action of hydrochloric acid and then hydrogen peroxide, afforded the 6-deoxy-6-hydroxyphosphinyl-D-fructopyranose derivative. This was converted into the 1,2,3,4,5-penta-O-acetyl-6-deoxy-6-methoxyphosphinyl-D-fructopyranoses, whose structure and conformation were established by H-1 NMR spectroscopy. (C) 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carres.2004.10.020

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

The addition of dimethyl phosphonate to six different hexofuranos-5-uloses in the presence of DBU, followed by esterification with methoxalyl chloride and then radical reduction, afforded 5-deoxy-5-dimethoxyphosphinyl-D- and L-hexofuranoses. The stereoselectivity of the deoxygenation and possible transition-state models are discussed. (C) 2003 Elsevier Ltd. All rights reserved.

DOI： 10.1016/S0008-6215(03)00235-0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

H-1 NMR spectroscopy of phosphorus containing hetero sugars (phospha sugars), revealed the alpha and beta configurations and chair conformations for 3-acetamido-1,4-di-O-acetyl-2,3,5-trideoxy-5-C-(isopropylphosphinyl)-alpha- and beta-D-erythro-pentopyranoses. The conformation of the title compounds was determined by H-1 NMR as C-1(4) in CDCl3 and the conformation was in accord with that in solid state determined by X-ray crystallographic analysis. (C) 2002 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0008-6215(02)00397-X

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：FREUND PUBLISHING HOUSE LTD  

H-1 NMR spectroscopy for phosphorus containing hetero sugars (phospha sugars (9a-d) under bar and (17a-d) under bar) revealed the stereoisomeric configurations and the chair conformations for alpha - and beta -1,2,4-tri-O-acetyl-3.5-di-deoxy-5-C-(isopropyl- and phenyl-phosphinyl)-D-erythro-pentopyranoses. The conformations of the title compounds were characterized as C-4(1) chair form in CDCl3 by H-1 NMR (500 MHz), and the conformations were in accord with those in the solid state determined by X-ray crystallographic analyses.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Starting from methyl 2,3-O-isopropylidene-alpha-D-mannofuranoside (5), methyl 6-O-benzyl-2,3-O-isopropylidene-alpha-D-lyxo-hexofuranosid-5-ulose (12) was prepared in three steps. The addition reaction of dimethyl phosphonate to 12, followed by deoxygenation of 5-OH group, provided the 5-deoxy-5-dimetltoxyphosphinyl-alpha-D-mannofuranoside derivative 15a and the beta-L-gulofuranoside isomer 15b. Reduction of 15a and 15b with sodium dihydrobis(2-methoxyethoxy)aluminate, followed by the action of HCl and then H2O2, afforded the D-mannopyranose (17) and L-gulopyranose analog 21, each having a phosphinyl group in the hemiacetal ring. These were converted to the corresponding 1,2,3,4,6-penta-O-acetyl-5-methoxyphosphinyl derivatives 19 and 23, respectively, structures and conformations (C-4(1) or C-1(4), resp.) of which were established by H-1-NMR spectroscopy.

DOI： 10.1002/1522-2675(200209)85:9<2608::AID-HLCA2608>3.0.CO;2-F

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The addition reaction of dimethyl phosphonate to 3,6-di-O-benzyl-1,2-O-isopropylidene-alpha -L-arabino-hexofuranos-5-ulose (11), followed by deoxygenation of 5-hydroxyl group, provided 5-deoxy-5-dimethoxyphosphinyl-D-galactofuranose derivative (13a). Reduction of 13a with sodium dihydrobis(2-methoxyethoxy)aluminate, followed by the action of hydrochloric acid and then hydrogen peroxide, afforded the first D-galactopyranose analog (15) having a phosphinyl group in the hemiacetal ring. This was converted into the 1,2,4-tri-O-acetyl-5-methoxyphosphinyl derivatives (16), whose structure and conformation were established by H-1-NMR spectroscopy.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

By starting with known 3,6-di-O-benzyl-1,2-O-isopropylidene-alpha-D-xylo-hexofuranos-5-ulose (5), the 3,6-di-O-benzyl derivatives (8 and 10) of the title phospho-sugar analogs were prepared in six steps through the key intermediates, 5-deoxy-5-dimethoxyphosphinyl- 1,2-O-isopropylidene-alpha-D-gluco- and -L-idofuranoses (7a and 7b), respectively. These products (8 and 10) were respectively converted into the corresponding 1,2,4-tri-O-acetyl-5-methoxyphosphinyl derivatives (9 and 11), whose structures and conformations (mostly in C-4(1)) were established by spectroscopy.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SCIENCE REVIEWS LTD  

3,6-Di-O-benzyl-5-deoxy-5-dimethylphosphinyl-1,2-O-isapropylidene-alpha-D-glucofuranose 5 was converted, in four steps, into methyl 2-acetamido-3,6-di-O-benzyl-2,5-dideoxy-alpha-D-mannofuranoside which led to 3,5-di-O-benzyl derivatives 9 of a P-in-the-ring D-mannosamine analogue.

DOI： 10.1039/a804961k

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Additivity constants for phosphorus were estimated for the prediction of vicinal H-1-H-1 coupling constants by means of an additivity rule in a series of pyranose analogs having phosphorus as the ring heteroatom. The experimental J values were well reproduced by employing the proposed additivity constants with a small overall root-mean-square difference of 0.32 Hz. The prediction of coupling constants was employed for the investigation of conformational equilibria of pyranose analogs having a phosphinyl group in the ring or on the ring-carbon. (C) 1998 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0008-6215(97)10038-6

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：BLACKWELL WISSENSCHAFTS-VERLAGGMBH  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：INT SOC PTERIDINOLOGY  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：INT SOC PTERIDINOLOGY  

Treatment of L-biopterin (1) with N,N-dimethyformamide dimethyl- (or diethyl)acetal and then with acetic anhydride in pyridine gave 1',2'-di-O-acetyl-N2-(N,N-dimethylaminomethylene)-L-biopterin (4), which was converted by the Mitsunobu reaction into 3-methyl (5) and 3-p-nitrophenetyl derivatives (7). The protective groups on the side chain diols and N2 of these compounds were selectively cleaved to furnish products 6, 8-10, among which 9 is naturally occurring 3-methyl-L-biopterin and 8 is N2,N(3)-protected biopterin, a versatile intermediate for various reactions on the side-chain diol. In contrast, the same Mitsunobu reactions of tri-N2:1',2'-O-acetyl-L-biopterin (11) afforded O4-methyl (12) and O4-NPE derivatives (13), both of which yielded O4-methyl-L-biopterin (14) and subsequently led to 4-amino-L-biopterin (18).

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Arbuzov reaction of 1,4-dibromo- or 1,4-diiodo-1,4-dideoxy-2,3-di-O-methyl-L-threitol with diethyl phenyl phosphonite readily afforded (4R,5R)-4,5-dimethoxy-2-oxo-2-phenyl-1,2-oxaphosphorinanes 7a (C-2(5)) and 7b (C-5(2)), a 1-phosphonopentopyranose, via non-isolable ethyl 4-bromo-2,3-dimethoxybutylphenylphosphinate precursors 6a,b.

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

The title sugar analogue (9) was conveniently synthesized from known 3-O-acetyl-5,6-dideoxy-5-dimethoxyphosphinyl-1,2-O-isopropylidene-6-nitro-alpha-D-glucofuranose in 4 steps via the 6-t-butoxycarbonylamino derivative. The structure of 9 was established by spectroscopy after conversion into the 6-acetamido-1,2,3,4-tetra-O-acetyl-5-methoxyphosphinyl derivatives.

DOI： 10.1246/bcsj.67.2596

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Treatment of 1-alkoxy-3-phospholene 1-oxide with lithium diisopropylamide followed by novel stereoselective C-alkylation with alkyl halides afforded 2-alkyl- and 2-benzyloxymethyl-3-phospholene 1-oxides, which were subjected to osmium (VIII) oxide-catalyzed diastereoselective cis-dihydroxylation to give new C-glycoside derivatives of furanose-type phosphono sugars, with twist conformation.

DOI： 10.1246/cl.1993.93

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：PLENUM PRESS DIV PLENUM PUBLISHING CORP  

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOC SYNTHETIC ORGANIC CHEM JPN  

Synthetic studies are reviewed on sugar analogs containing a phosphorus atom in the hemiacetal ring, e.g., analogs of D-xylo, D-gluco, 6-deoxy-L-galacto. D-mannopyranoses, as well as D-ribo and 2-deoxy-D-ribofuranoses. These compounds were converted into the corresponding per-O-acetyl derivatives, whose structures and conformations were established by H-1-NMR spectral analyses and partly by X-ray crystallographic analyses. Stereoselectivity of the introduction of a phosphinyl group to various types of 6-O-tosyl-hex-5-uloses and 6-nitro-hex-5-enoses are also described.

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1246/bcsj.66.2315

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

3-O-Benzyl-1,2-O-isopropylidene-6-O-tosyl-alpha-D-allofuranose was led to methyl (5R and 5S)-3-O-benzyl-5, 6-dideoxy-5-[(methoxy)phenylphosphinyl]-D-ribo-hexofuranoside (9) in a 4 step sequence (55% overall yield). Methyl (5R and 5S)-2-acetamido-2,5,6-trideoxy-5-[(methoxy)phenylphosphinyl]-D-arabino-hexofuranoside (12) was prepared from 9 in 4 steps involving a C-2 inversion (62% overall yield). Compound 12 was then converted, in 2 steps, into the title compound, which was characterized as the peracetyl derivatives.

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Language：English   Publisher：CHEMICAL SOC JAPAN  

The addition of dimethyl phosphonate to six 5,6-dideoxy-6-nitro-D-hex-5-enofuranoses at 25-degrees-C in the presence of triethylamine preponderantly gave (5R)-adducts, whereas the same reaction at 100-degrees-C without a base yielded (5S)-adducts as the main products.

DOI： 10.1246/bcsj.65.1154

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

X-ray crystallographic analyses are reported for the two title compounds (8 and 9), of which the former crystallized in two modifications (8a and 8b). In all three structures, the pyranose rings have the C-4(1) (D) conformation and the substituents at C-1 are axial and those at C-2-C-4 are equatorial. The phenyl rings are oriented equatorially with their planes nearly parallel to the axial P = R bond (R = O, S). The favored conformations of various PhP(= R)-in-ring D-xylopyranose acetates (R = O, S, lone-pair;8-19) in solution are discussed. The inclination of the equatorial P-phenyl group of the alpha- and beta-D-xylopyranose analogs 8-13 is similar to that observed in the solid, whereas the inclination of the axial phenyl ring of the P-5 epimers 14-19 is near 90-degrees with respect to the equatorial P = R bond.

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

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Authorship：Lead author   Language：English   Publisher：The Chemical Society of Japan  

1,2-O-Isopropylidene-3-O-methyl-6-O-tosyl-β-<small>D</small>-arabino-hexofuranos-5-ulose (9a) and its 3-O-benzyl congener (9b) were prepared from 1,2:5,6-di-O-isopropylidene-β-<small>D</small>-altrofuranose in 4 steps. Addition of methyl phenylphosphinate to 9a and 9b in the presence of DBU, followed by reduction with Raney Ni, afforded (5R and 5S)-5,6-dideoxy-1,2-O-isopropylidene-5-[(methoxy)phenylphosphinyl]-3-O-methyl-β-<small>D</small>-arabino-hexofuranose(11a) and 3-O-benzyl congener (11b), respectively. The latter compound (11b) was debenzylated to 3-O-unsubstituted hexofuranose 11d. By reduction with sodium dihydrobis(2-methoxyethoxy)aluminate, followed by acid hydrolysis, these key intermediates 11a, 11b, and 11d provided the title <small>L</small>-fucoses 13 (together with a minor proportion of <small>D</small>-altropyranoses 14) having as phenylphosphinylidene group in place of the ring oxygen. Compounds 13 and 14 were converted into per-O-acetyl derivatives for structural and conformational analysis by spectroscopy.

DOI： 10.1246/bcsj.64.869

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

2,3-O-Isopropylidene-D-glyceraldehyde reacts with dimethylphosphine oxide in the presence of triethylamine to give separable (1S,2R)- and (1R,2R)-l-dimethylphosphinylglycerol (65:35), from which the (1R) and (1S) title compounds are respectively derived via 1-O-mesyl and 1-azido derivatives. The corresponding 1-dimethoxyphosphinylglycerols are similarly prepared. Structural and conformational assignments of these products are made on the basis of the H-1 NMR data and [alpha]D values.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

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DOI： 10.1246/bcsj.62.2320

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

DOI： 10.1021/jo00255a023

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

DOI： 10.1021/jo00219a018

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

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