The photolysis of o-azidobenzoic acid derivatives: a practicable synthesis of 2-alkoxy-3-alkoxycarbonyl-3H-azepines

Abstract

and OBz) in methanol, or methanol-tetrahydrofuran solution, yields in the majority of cases 3-substituted 2methoxy-3H-azepines. Substituted methyl 2-azidobenzoates (X-2-N,C6H,C0,Me; X = CI, OMe, NO,, Br.CO,Me, and C0,H) give the correspondingly substituted 2-methoxy-3-methoxycarbonyl-3H-azepines depending on the nature and position of the substituent group (X). In contrast, thermolysis of methyl o-azidobenzoate in alcohol solution gives mixtures of 3H-azepines and triplet nitrene derived products.

Preparation of Fused Tetracyclic Quinazolinones by Combinations of Aza‐Wittig Methodologies and CuI‐Catalysed Heteroarylation Processes

“…The starting iminophosphoranes 4 (Scheme 2) have been prepared by the following two-step process: (a) acylation of the appropriate arylamines 2 with o-azidobenzoyl chloride (1) [8] in dichloromethane in the presence of pyridine to give the N-aryl-substituted o-azidobenzamides 3 in 77-90 % yields, and (b) Staudinger reactions between the azides 3 and triphenylphosphane in dichloromethane at room temperature to give the iminophosphoranes 4 in almost quantitative yields (95-98 %, Table 1). Aza-Wittig reactions between the iminophosphoranes 4a-d and benzyl isocyanate in dry toluene at reflux temperature then provided the 2-benzylamino-substituted quinazolinones 5 in low yields ranging from 5 to 80 % (Scheme 3, Table 2).…”

Photochemistry of fluorophenyl azides in aniline

“…[19][20][21][22]. In another study [7], photolysis in diethylamine of aryl azides 15 bearing an ortho substituent (R ¼ CH 3 , C 2 H 5 , i-C 3 H 7 , C 6 H 5 ) gave a single isomeric azepine 16.…”

“…This reaction has been studied for many years and several reaction pathways have been proposed to explain the products formed. The singlet state nitrene 2 is considered the first intermediate formed upon photolysis of phenyl azide and improved spectroscopic techniques have allowed direct observation of this short lived intermediate [10,14,15,21]. This singlet nitrene can undergo ring insertion to form a bicyclic azirine 5 or ring expansion to form a didehydroazepine 4 that can be trapped to give synthetically useful yields of azepine 7.…”

N-Alkylation and Aminohydroxylation of 2-Azidobenzenesulfonamide Gives a Pyrrolobenzothiadiazepine Precursor Whereas Attempted N-Alkylation of 2-Azidobenzamide Gives Benzotriazinones and Quinazolinones

“…Compounds ( 9 ) to ( 15 ) 10,24,53 and ( 20 ) 24,27,28 were synthesized as described in the literature. The methods that we used to access racemic ( 16 ) and ( 3 ) are methods that we developed previously to produce enantiopure ( 16 ) and ( 3 ).…”