2-Chloroethanol decomposes at 430-496� into acetaldehyde and hydrogen chloride with first-order rate given by: k1 = 1012.8�1 exp(-229700 � 4000/8.314T) s-l The rate is slightly less than that for ethyl chloride. That acetaldehyde is the product shows that a 1-2 shift of hydrogen has taken place and this is indicative of a polar transition state.The acetaldehyde subsequently decomposes to methane and this decomposition is catalysed by the hydrogen chloride produced.
Experiments were conducted to determine the effect of heating field peas (Pisum sativum) on the N balance and urine, serum and plasma composition of growing pigs. In the first experiment, four diets containing raw field peas (cv. Wirrega) (cv. Wirrega) or 165" (cv. Wirrega) had a significantly lower (P c 0.01) daily output of urea and uric acid in the urine, and depressed serum protein and serum urea concentrations. P h a lysine concentration and daily urine lysine output were not significantly different (P > 0.05) in pigs fed OD heated peas. Protein excretion in the urine of pigs fed on diets containing peas heated to 165" increased 3-7 times (depending on estimation technique) the level observed in pigs fed on diets containing raw peas. A second experiment was conducted to determine the apparent ileal digestib~ty of N and amino acids in cv. Wmega field peas. This study revealed that N digestiiility (044) and lysine digestibility (0.35) in peas heated to 165" were significantly lower than the cv. Dundale estimates (0.57 and 0-62 respectively) used in diet formnlations. The depressed serum and urine variables in pigs fed on heated peas were attributed to overestimation of digestibility.The results exemplify the fact that it is not possible to draw general conclusions as to the effects of heat on any particular protein concentrate. Variability in N balance experiments and problems associated with urine analysis are suggested as likely reasoms for the carrent study not reflecting poor utilization of ileal digestible lysine from heat-treated field peas. Despite considerable variation in the results, it is possible that a large proportion of non-utilizable amino acids in heated field peas may be excreted from the pig via the urine in the form of a protein.Field peas: Heat treatment: Nitrogen: Pigs Amino acid availability measurements have been shown to reflect the poor utilization of * Present address: Northfield
Reduction of three 1?-oxoisochromeno(4?,3?:2,3)chromones [chromeno(3?,2?: 3,4)isocoumarins] with lithium aluminium hydride has been shown to yield 3(3?)-hydroxyisochromano(4?,3?:2,3)chromans (hemiketals). The structures of these compounds (the 7-methoxy, 7,6?,7?-trimethoxy, and parent hemiketals) were unequivocally established by N.M.R., mass spectral, and chemical data. The hemiketals contain the peltogynol ring system, and one of them is the 7,6?,7?- trimethyl ether of the structure originally proposed for this leucoanthocyanidin by Robinson and Robinson. The hemiketals were obtained as mixtures of cis- and trans- isomers which underwent equilibration in deuterochloroform or in wet chloroform, and configurations were assigned to the isomers from a detailed study of their N.M.R. spectra. The hemiketals suffered dehydration when heated further in deuterochloroform, and gave the isochromeno(4?,3?:2,3)chromens (flav-2-enes), which immediately gave the flavylium salts with cold acids in air. The flavylium salts were also formed very readily from the hemiketals and acid, and the trimethoxy- henliketal gave the peltogynidin trimethyl ether cation. In connection with the mechanism of formation of the hemiketals from chromenoisocoumarins it was found that 2?-hydroxychalcones are reduced by sodium borohydride to flav-3-enes, and these readily give anthocyanidins when treated with acid. Parallel biological reduction of chalcones is clearly possible and a plausible, new, biosynthetic pathway leading directly from 2?-hydroxychalcones to anthocyanidins and catechins is proposed. Flav-3-enes are valuable intermediates for preparation of flavans, flavan derivatives, and flavylium salts, and the new synthesis makes flav-3-enes readily accessible in one stage from 2?-hydroxychalcones.
The chemical synthesis, on a 10–30 μmol scale, of two series of puromycin analogues is described: the first is the type 3′-N-aminoacyl-puromycin aminonucleoside (e.g. 3′-N-glycyl-PANS or PANS-Gly) in which the O-methyl-L-tyrosyl residue of puromycin is replaced by various aminoacyl residues, and the second is the type NpPANS-Gly in which the 5′-hydroxyl of PANS-Gly is substituted with phosphate, 3′-AMP, 3′-CMP, 3′-GMP, or 3′-UMP. The 3′-N-aminoacyl-PANS derivatives were synthesized either by coupling N-protected amino acids via their N-hydroxysuccinimide esters to PANS in 70% aqueous pyridine or by direct coupling in ethanol or methanol of N-protected amino acids to PANS using N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) as condensing agent After removal of the protecting groups, reaction mixtures were purified by preparative thin-layer chromatography on silicic acid, paper chromatography, and paper electrophoresis to give the 3′-N-aminoacyl-PANS derivatives in yields of 40–80%.The 5′-O-nucleotidyl derivatives of PANS-Gly were synthesized by three methods: (i) by the coupling of fully acetylated 3′-mononucleotides to 3′-N-(Boc-glycyl)-PANS, (ii) by the coupling of N4-acetyl-2′,5′-di-O-tetrahydropyranylcytidine or N2,O2′,O5′-tritetrahydropyranylguanosine to 5′-O-phosphoryl-(Boc-glycyl)-PANS, and (iii) by the coupling of N4-acetyl-2′,5′-di-O-tetrahydropyranyl-3′-CMP or N2,O2′,O5′-tritetrahydropyranyl-3′-GMP to 3′-N-Boc-PANS or 3′-N-trifluoroacetyl-PANS followed by aminoacylation of the CpPANS or GpPANS produced with Boc-glycine and EEDQ. Coupling reactions were carried out using either N,N′-dicyclohexylcarbodiimide or 2,4,6-triisopropylbenzenesulfonyl chloride as condensing agents in anhydrous pyridine. After removal of protecting groups, reaction mixtures were purified by paper chromatography and paper electrophoresis to give the NpPANS-Gly derivatives in 3–30% yield.
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