摘要:

AbstractThe rearrangement of ethoxyethynyl‐carbinols into unsaturated esters was investigated in acidic aqueous solution. The reaction is general acid catalyzed and β‐hydroxy esters are by‐products. There exists a simple relation between the ratio of β‐hydroxy ester to unsaturated ester and the concentration of hydroxyl and acetate ions. The two products are formed in a common rate determining step, which is a proton addition to the β‐carbon atom of the carbinol. It is suggested, that the hydroxyl group participates and that a four‐membered ring intermediate is formed in this slow step:Ethylthioethynyl‐carbinols

ISSN:0165-0513    

DOI:10.1002/recl.19610801202

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractThe syntheses are described of glycyl‐α‐L‐aspartyl‐L‐serylglycine ethyl ester and of the O‐acetylated derivative. The tetrapeptide ethyl esters were obtained by coupling two dipeptide derivatives using the mixed anhydride method, followed by removal of the blocking groups. The dipeptide derivatives were synthesised by the

ISSN:0165-0513    

DOI:10.1002/recl.19610801203

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractThe merits and defects of the so‐called Auwers‐Skita Rule and of the Conformational Rule are discussed. A new rule, the Isomer Sequence Rule, is propo

ISSN:0165-0513    

DOI:10.1002/recl.19610801204

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractBF3forms a 1:1 complex with ϵ‐caprolactam and also with N‐methyl caprolactam. These complexes were investigated by means of I.R. spectroscopy and proton resonance. Both methods clearly showed that in these complexes the BF3is bound to ox

ISSN:0165-0513    

DOI:10.1002/recl.19610801205

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractThe ethyl hemiacetal of ethyl glyoxylate (ethyl ethoxy‐hydroxyacetate, I) has been found to undergo thermal condensation with various ketones. The new reaction presents a simple method of attaching a hydroxyacetic ester side chain to a carbon atom adjacent to the carbonyl function, giving 2‐hydroxy‐4‐keto‐alkanoic esters. Of several transformations to which these esters are readily accessible the dehydration reaction in particular has been inv

ISSN:0165-0513    

DOI:10.1002/recl.19610801206

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

Abstract1‐(3′‐Iodophenyl)‐5‐methyl‐1,2,3‐triazolecarboxylic acid, 1‐(4′‐iodophenyl)‐5‐methyl‐1,2,3‐triazolecarboxylic acid and 1‐(3′‐4′‐di‐iodophenyl)‐5‐methyl‐1,2,3‐triazolecarboxylic acid were prepared by reacting ethyl acetylacetate with the corresponding 1‐azido‐di‐iodobenzene.5‐Methyl‐1‐phenyl‐1,2,3‐triazolecarbonyl chloride and 1‐(4′‐iodophenyl)‐5‐methyl‐1,2,3‐triazolecarbonyl chloride were condensed with 3‐amino‐2,4,6‐tri‐iodobenzoic acid, α‐ethyl‐3‐amino‐2,4,6‐tri‐i

ISSN:0165-0513    

DOI:10.1002/recl.19610801207

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractThe composition and molecular size of enzymatically synthesized polyadenylic and polyuridylic acids (poly‐A, poly‐UThe following abbreviations will be used: ADP, UDP, etc. 5′‐diphosphates of adenosine, etc.; poly‐A, ‐U, etc. polynucleotides: polyadenylic acid, etc.; poly(A + U), etc. helical aggregates of the polynucleotides; RNA ribonucleic acid; DNA deoxyribonucleic acid. Different preparations of poly‐A and poly‐U are indicated ase.g.poly‐AB 55, poly‐UB 6B, poly‐AO 7. Chemical and physical data about these preparations are collected in Table V.) have been studied. The analyses comprised molecular weight, polydispersity, content of nitrogen, phosphorus, carbon, and hydrogen and the presence of residual protein, ‘foreign’ nucleotides, metal ions, and water. Some general aspects of the aggregation of poly‐A and poly‐U were also in

ISSN:0165-0513    

DOI:10.1002/recl.19610801208

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractN,N′‐Carbonyldi‐s‐triazole is shown to be a useful peptide‐forming reagent. Advantages over other reagents are: (1) low degree of racemization, (2) applicability in dimethylformamide, a solvent for both small and large

ISSN:0165-0513    

DOI:10.1002/recl.19610801209

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractWhen reacted with potassium amide in liquid ammonia, both 3‐chloro and 4‐chloropyridine are converted into a mixture containing 3‐amino and 4‐aminopyridine in a ratio of 1:2. The same reaction product results from the animations of 3‐iodo and 4‐iodopyridine. The course of these reactions can be explained by a mechanism involving 3,4‐pyridyne as an intermediate. 2‐Chloro and 2‐iodopyridine only yield 2‐aminopyridine.Rearrangementsviaethoxy derivatives of 3,4‐pyridyne probably proceed in aminations of 3‐bromo‐6‐ethoxypyridine and 4‐bromo‐5‐ethoxypyridine. A shift of the substituent from position 3 to 2 occurs in the amination of 3‐bromo‐4‐ethoxypyridine which yields 2‐amino‐4‐ethoxypyridine.An abnormal rearrangement takes place during the amination of 2‐bromo‐6‐ethoxypyridine, 4‐amino‐6‐ethoxypyr

ISSN:0165-0513    

DOI:10.1002/recl.19610801210

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19610801211

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY