Heptulosonic acid analogues

A more direct access to heptulosonic acid analogues have been described on [4+3] carbon atoms incorporation [156]. The Mukaiyama reaction of frans-a,P-epoxyaldehydes with ethyl 2-(trimethylsililoxy)-2-propenoate, in the presence of the Lewis acid - BF3 etherate - led to the direct synthesis of a mixture of 5- and 6-fluoroheptulosonic analogues in their pyranosidic or furanosidic form [156],... 

J. Mlynarski and A. Banaszek, A novel chemical synthesis of a 3-deoxy-D-arabino-heptulosonic acid 7-phosphate (DAHP) derivative and its 2-deoxy analogue, Carbohydr. Res., 295 (1996) 69-75. 

Tri- and tetra-peptide analogues incorporating an a-atnino acid at the anomeric position, e.g. 33, were synthesized by way of a novel oxidative ting contraction of 2-amino-2-deoxy-heptonic acid derivative 31 to give heptulosonic acid glycosylamine 32 and its anomer (Scheme 6). The spirocyclic diketopiperazine 35 was obtained from 34 it could be 0-deprotected under acidic conditions then anomerized to the thermodynamically favoured C-2 q>imer with strong base. See also reference 3 for a general route to anomeric a-amino acids. 

The syntheas of glyco ltetrazoles as analogues of 3-deoxy-D-arafrino-heptulosonic acid 7-phosphate (DAHP) and 2-deoxy DAHP is mentioned in Chapter 3. 

A chemical route to the non-phosphorylated heptulosonic acid is indicated in Scheme 7.16,17 7 5 phosphonate analogues (17) and (18) of DAHP(16) have been synthesized, along with the analogues (19) and (20)... 

The isolation and characterization of several new isomers of (-) quinic acid, obtained by boiling quinic acid in a mixture of acetic and sulfuric acids in order to obtain reference materials for identifying components of roasted coffee, has been achieved/ Quinic acid has also been used in a short synthesis of compound (43), a phosphonate analogue of a reactive intermediate formed during 3-dehydroquinate synthase (DHQ synthase)-catalysed conversion of 3-deoxy-D-arabjno-heptulosonic acid-7-phosphate (DHAP) to 3-dehydroquinate (DHQ), as an irreversible inhibitor of DHQ synthase/ ... 

The periodate oxidation of 9-O-acetyl and 4,9-di-O-acetyI derivatives of the methyl ester of 7V-acetyl-)8-D-neuraminic acid methyl glycoside has been studied the 9-O-acetyl group was found to hinder the oxidation, thus accounting for the low molar absorbancy coefficient of such derivatives in the periodate-thiobarbituric acid assay. The reactivity of a seven-carbon analogue of AT-acetylneuraminic acid, namely 5-acetamido-3,5-dideoxy-L-ara //io-heptulosonic acid, in the thiobarbituric acid and resorcinol assays has also been evaluated and the formation of the various chromophores discussed. ... 

A short review (11 pages, 14 references) on the synthesis and evaluation of mechanism-based inhibitors of Kdo8P synthase has appeared. " A review on the alkaline biocatalysis for the direct biosynthesis of iV-acetyl-D-neuraminic acid (NeuSAc) from iV-acetyl-D-glucosamine has also been written. The syntheses of furanose derivatives of 3-deoxy-D-cryt/iro-2-hexulosonic acid and their 3-bromo and 3-deuterio analogues have been reported. 3-Deoxyoctulosonic acid 16 has been prepared by use of E. coli heptulosonate synthase (Scheme 6). ... 

The first enzyme which is specific for aromatic amino acid biosynthesis is 3-deoxy-D-arabino-heptulosonic 7-phosphate (DAHP) synthase (EC 4.1.2.1.5), which utilizes D-erythrose 4-phosphate (E4P) and phosphoenolpyruvate (PEP) as substrates (Fig. 2). Le Mar chal al.prepared the isosteric homophosphonate of E4P, in which the C-O-P group is replaced by the C-CH2-P group as well as the non-isosteric phosphonate analogue, in which the C-O-P group is replaced by the C-P group (Fig. 3). Both analogues served as substrates for the tyrosine-sensitive DAHP synthase of Escherichia coli, with Vmax values in the ratio 20 3.5 1 for E-4-P, the phosphonate, and the homophosphonate. 

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