Hydrolyzed, xxii

A 5-benzyl-D-ribose has been prepared by Kenner, Taylor and Todd,90 who etherified the methyl 2,3-isopropylidene-D-ribofuranoside (XXI) of Levene and Stiller91 with benzyl chloride to obtain methyl 2,3-iso-propylidene-5-benzyl-D-ribofuranoside (XXII), which was subsequently hydrolyzed to give amorphous 5-benzyl-D-ribose (XXIII). The structure of this ether was confirmed through acetylation to its triacetate (XXIV), hydrogenolysis to 1,2,3-triacetyl-D-ribofuranose (XXV) and further acetylation to the known, crystalline tetraacetyl-D-ribofuranose (XXVI). 

Neither of the linkages formed by reactions (XXI) or (XXII) has been demonstrated in alkali-treated wool, but Patchornik and Sokolovsky (1964) and Bohak (1964) have demonstrated recently the presence of -iV-(D,L-2-amino-2 carboxymethyl)-L-lysine in hydrolyzates of proteins treated with alkali. This they attribute to the reaction of the -NH2 group of lysine residues with a-aminoacrylic acid residues formed from cystine residues by the 8-elimination reaction (Section V,A,5). Ziegler (1964) has shown that this amino acid residue is formed during the alkali treatment of wool in both the stretched and unstretched states. No assessment of the importance of these linkages in retaining set has yet been reported. 

Isolated from Datura ferox L. 29), this product was hydrolyzed to (— )-3a,6/S-tropanediol and ( —)-tropic acid. A synthesis of XXI was achieved by hydrogenolytic cleavage (30) of A — )-hyoscine (XXII), obtained by total synthesis, and followed by separation of the diastereo-isomeric S( — )-tropoyltropanediols with dibenzoyltartaric acid. Feeding D. stramonium L. seedlings with hyoscyamine-(methyl-i4C) brought about its conversion to the 6 3-hydroxy derivative-(methyl-i C) 31). 

Acid derivatives First, various pyrimido[4,5-b]quinoline-2-carboxylic acid derivatives were examined (Figure 5). The nearly equal activity of the acid VI and corresponding ethyl (VII) and butyl (XX) esters suggests that the acid is the active species. However, the ethyl ester is definitely advantageous for oral activity, being nearly 10 times more potent than the butyl ester or the carboxylic acid. This suggests that the lipophilic character of the ester is important for oral absorption. The carboxamide (XXI) which may not be readily hydrolyzed to the acid in vivo exhibits significantly reduced potency both intravenously and orally, and the N-ethyl carboxamide (XXII) is inactive at comparable doses. 

While XXI can be hydrolyzed with warm water to afford the starting dichloromaleic imide, XXII is considerably more stable. 

The significance of imidoyl halides as intermediates in the Beckmann rearrangement has been pointed out earlier (see Chapter 3). In the Chapmann rearrangement imidoyl chlorides are used to prepare imidates, which undergo rearrangement to yield N-aroyl derivatives of diarylamines C ). For example, reaction of the sodium salt of dimethyl 4,6-dihydroxyisophthalate (XIX) with the benzimidoyl chloride XX yields the bis-imidate XXI, which can be thermally rearranged and hydrolyzed to produce the diamines XXII C). 

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