Valienamines derivatives

They also prepared valienamine derivative (+)-227 from the ditosylate (294) derived from 286. The spiro epoxide (295) obtained from 294 was converted into 296 by treatment with selenoxobenzothiazole-tri-... 

The total synthesis of the trehalose inhibitor salbostatin 451 was achieved by the coupling reaction of the a-valienamine derivative 449 with l,5 2,3-dihydro-D-maimitol (450) imder forcing conditions (sealed tube, 120°C) in a protic solvent [265] (compoimds 449-451),... 

The trehalase inhibitor salbostatin (7) has been synthesized (Scheme 1) via interaction of l,5 2,3-dihydro-D-mannitol (6) with the known a-valienamine derivative 5 some of the product of diaxial opening of the epoxide was also produced, although the desired regioisomer was isolated in 58% yield. ... 

Among the carba-sugar derivatives, the most important and attractive members are amino carba-sugars, particularly 5a-carba- -D-glucopyran-osylamlne (validamine) and its unsaturated derivative (valienamine). These amino carba-sugars have been synthesized successfully, as well as validamycin antibiotics and some of the aforedescribed enzyme inhibitors. 

Total synthesis of (+)-validamycins A and B starting from a common synthetic intermediate was elaborated by the following sequence. Tetra-(9-benzyl-(-l-)-valienamine (370), derived from 211, and the di-O-benzyl derivative (371) of the epoxide were coupled in 2-propanol to produce the protected dicarba compound (374), the structure of which was confirmed by conversion into (-1-)-validoxylamine B nonaacetate. Concurrently, compound 372 was glycosylated and the product oxidized with a peroxy acid, to afford a mixture of products from which the desired epoxide (373) was obtained in 70% yield. Coupling of 370 with 373 in 2-propanol at 120° afforded two carba-trisaccharides, and the major product (47%) was depro-tected and characterized as the dodecaacetate of validamycin B. The pro-... 

Among other carba-sugar derivatives, the most important compounds are amino carba-sugars having an amino group at C-1. They are known as validamine, valiolamine, hydroxyvalidamine, and valienamine, and are found in validamycin antibiotics as unique components they have been synthesized in dl forms and also in optically active forms. 

B. M. Trost, L S. Chupak, T. Lubbers Total Synthesis of ( )-and (+)-Valienamine via a Strategy Derived from New Palladium-Catalyzed Reactions , J. Am Chem Soc 1998,120,1732-1740. 

Only blastmycinone (36), valienamine (39), 40, 41, and 44 have no substituent at the branching carbon atom (Type B). A diversity (such as formyl, hydroxymethyl, methyl, 1-hydroxyethyl, acetyl, 2-hydroxyace-tyl, 1,2-dihydroxyethyl, higher alkyl, and carboxyl groups) is observed in the branchings, but, some of them are chemically interconvertible, and also can be derived from a common intermediate (see Scheme 1). 

In spite of the great biological potential of valienamine and its derivatives, only a few methods have been reported for their synthesis [56]. 

As shown in O Scheme 44, this method was also applied to total synthesis of (-i-)-valienamine (320) and (+)-validamine (324) [209]. Silyl enol ether 314 derived from D-xylose in nine steps... 

Total syntheses of (+)-validamycin B (compoimd 367) [199,200], ( + )-valida-mycin A(365) [201,202], validoxylamine B (362) [200], (+)-validoxylamine A(361) and (+)-validamycin E (compoimd 368) [202] have also been reported by the same group. In another report, cleavage of the imino bonds of validoxylamine A derivatives with A-bromosuccinimide was demonstrated. This method reports the preparation of synthetically useful derivatives of (+)-validamine and valienamine [203]. 

Valiolamine and its C-1 and C-2 epimers, together with other analogues, have been prepared from (-)-quinic acid and racemic validamine, together with its C-1 and C-2 isomers, have been synthesized from (phenylsulfonyl)-7-oxa-bi-cyclo[2.2.1]heptane derivatives. Six A-alkyl derivatives of P-valienamine have been made and shown to be potent and specific inhibitors of P-glucocerebrosi-dase the best was the -octyl derivative. ... 

The preparation of a glycosylceramide derived from 2,3 4,6-di-0-isopropylidene-P-valienamine as an analogue of glucosylceramide and of some carbaglycosylamides as glycolipid analogues have been described. 

A low yielding synthesis of 2-acetamido-5a-carba-2-deoxy-a-D,L-a//o- and gwlo-pyranose tetraacetates and some 3-acetamido-3-deoxy derivatives have been achieved starting from bicyclic acetate 87." By use of the same intermediate the preparations of valienamine and valiolamine have also been achieved." ... 

Ogawa and co-workers have continued to develop syntheses of a large number of racemic branched-chain cyclltols, many related to natural products, from a common original starting material - the Diels-Alder adduct of acrylic acid and furan (see Vol.ll, p.l50 and Vol.13, p.l54). The structure of hydroxyvalidamine, a component of validamycin B, has been confirmed by the synthesis of Its racemic hexaacetate the racemic derivative (43) could be synthesized more efficiently, using the dibromide (44) and the cyclohexene (45) (Scheme 8). Syntheses of racemic valienamine CHgBr CH2OBZ 0—I OAc... 

The oligosaccharides acarbose and adiposin-2 have been synthesized by coupling protected valienamine to a trisaccharide 3",4"-epoxide derived from 1",6"-anhydro-maltotriose the anticipated... 

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