Henk Regeling

Syntheses of (3R,4R,5R,6R)-tetrahydroxyazepane (1,6-dideoxy-1,6-imino-d-mannitol) and (3S,4R,5R,6R)-tetrahydroxyazepane (1,6-dideoxy-1,6-imino-d-glucitol)

Abstract Syntheses of 1,6-dideoxy-1,6-imino- d -mannitol ( d -mannoazepane) ( 1 ) and 1,6-dideoxy-1,6-imino- d -glucitol ( d -glucoazepane) ( 3 ) from d -isoascorbic acid and d -glucono-1,5-lactone, respectively, are described. The key step in both routes involved reductive aminative 1,6-cyclization with retention of configurations to give the corresponding lactams, which were subsequently reduced to afford compounds 1 and 3 in 24 and 28.5%, overall yield, respectively.

Synthesis of 1-deoxy-L-gulonojirimycin (L-guloDNJ) and 1-deoxy-D-talonojirimycin (D-taloDNJ).

Carbohydrate based syntheses of azasugars with unusual configurations viz. 1,5-dideoxy-1,5-imino-L-gulitol (L-guloDNJ) and 1,5-dideoxy-1,5-imino-L-talitol (L-taloDNJ) are reported, from D-mannose and D-fructose, respectively. The key steps in both syntheses involved reductive aminative cyclizations. Thus, L-guloDNJ was obtained by reduction of 2,3;4,6-di-O-isopropylidene-5-O-p-toluenesulfonyl-D-mannononitrile with LiAlH(4) in DME to give the protected azasugar which upon hydrolysis with HCl afforded crystalline L-guloDNJ as the HCl salt in 29% overall yield. Reduction of 6-azido-1-O-tert-butyldimethylsilyl-2,3-O-isopropylidene-beta-D-ribohexulofuranose obtained from D-fructose in six steps, followed by treatment with HCl, afforded L-taloDNJ as an HCl salt in approximately 10% overall yield.

Synthesis of some trideoxy-d-hexoses and derivatives thereof from d-glucono-1,5-lactone☆

Abstract Enantiospecific syntheses of methyl 2,3,4-trideoxy-α- d - and -β- d -glycero-hexopyranoside (10 and 11) methyl α- d - and β- d -amicetopyranoside (24 and 25), (2S)-1,2-hexanediol (36), (2S)-1,2,6-hexanetriol (37), and some derivatives thereof from d -glucono-1,5-lactone are described.

Decyl and dodecyl β-d-fructofuranosides

Abstract Decyl and dodecyl β- d -fructofuranosides are formed from d -fructose and catalysed by boron trifluoride alcoholates, in admixture with the corresponding α- d anomers and β- d -pyranosides. These were separated by chromatography and each of the products was fully characterized by NMR spectroscopy and as tetrakis(p-nitrobenzoates).

Enantiospecific syntheses of (R)- and (S)-proline and some derivatives from D-glucono-1,5-lactone

Carbohydrate-based enantiospecific syntheses of (R)-proline 1 and (S)-proline 2 from the previously reported D-erythro-hexonate ester 9 are described. Azide-substitution reactions on appropriately activated intermediates derived from ester 9, followed by reductive cyclization (H2/Pd–C), gave the substituted pyrrolidines 14 and 22, which were converted into their corresponding N-Cbz derivatives 16 and 24 in conventional manner. Mild acidic hydrolysis of these, followed by oxidation (sodium metaperiodate), gave the protected prolinals 3 and 4, which on further oxidation (sodium chlorite), followed by catalytic hydrogenolysis, gave the prolines 1 and 2. The N-Cbz-prolinol derivatives 5 and 6 are also reported.

Synthesis of some monodeoxy- and dideoxy-hexitols, and derivatives thereof, from d-glucono-1,5-lactone

Syntheses of 2-deoxy-D-arabino-hexitol (1), D-rhamnitol (2), 1,2-dideoxy-D-arabino-hexitol (3), 2,3-dideoxy-D-erythro-hexitol (4), and some derivatives thereof are described. These compounds were obtained by reductive sequences on various compounds formed from methyl 3,4:5,6-di-O-isopropylidene-D-gluconate (9).

Synthesis and reactions of some derivatives of (3,6S, 9R, 10R, 1 1S)-1,4,7-trioxaspiro[5,5]undecane-3,9,10,11-tetrol : novel quasi-saccharides

Abstract The title compound was obtained by reductive ozonolysis of allyl β- d -fructopyranoside. The synthesis and characterization of a number of C-3-substituted derivatives using conventional carbohydrate procedures is described. Some of the products may be of biological interest as carbohydrate mimics. The structures of two of the basic products (8 and 9) were substantiated by X-ray diffraction studies.