Lactim ethers, from lactams

Another example of the preparation of lactim ethers from lactams and phosphoryl chloride is the transformation of tetrahydro-/ -carbolin-l-one (19) to l-alkoxy-3,4-dihydro-/3-carboline (20)46,47 (Scheme 3). 

Presumably, the synthesis of lactim ethers from lactams and acylat-ing agents, including phosgene and ethyl chloroformate, proceeds via intermediate imidochlorides5 5 57 (Scheme 4). 

Stephen and Stephen set out from 2-chloro-3,4,5,6-tetrahydropyridine and methyl anthranilate and obtained the pyrido[2,l-i>]quinazolinone 205 (R = R = H, n = 1) in 75% yield. Alkyl anthranilates were also treated with lactim ethers and lactams. ... 

The reaction of lactim ethers with hydrazine and its derivatives proceeds readily. The resulting compounds are highly reactive and can be used in different reactions involving the side chain and the cyclic nitrogen atom.5,54,76> 80-82 For example, the treatment of caprolactam hydrazone (40) with nitrous acid results in pentamethyl-enetetrazole (41),54,80,81 and the use of diiferent lactim ethers gives other tetrazoles.32,35 The synthesis of polymethylenetetrazoles from lactim ethers and HN3,83 and also84 from HN3 and O-acyl lactims (or imidochlorides of lactams), obtained from lactams and sulfochlorides or phosphoryl chloride, may be mentioned. 

Tricyclic compounds of type 205 were produced in about 50% yield from the reactions of isatoic anhydride with lactams " and lactim ethers. ° When A -methylisatoic anhydride was applied instead of isatoic anhydride, the products were the unstable enamines 206, which may undergo further transformations depending on the reaction conditions. - - ... 

From the methods by which the polypeptides are obtained by synthesis it can only be concluded that their constituent amino acids are combined tc ether in the form of acid amides this method of combination also occurs in the case of the oxyaraino acids, e.g.., leucyl-isoserine, where the ester method of combination was excluded by special investigations. The question of their structure, however, still remains very complex, if the controversy concerning the structure of the amides and amino acids, which has not yet been settled, be taken into account. There is the possibility of lactam and lactim forms and of the free amino add and intramolecular salt these are illustrated by the four formulae for glycyl-glycine —... 

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