Studies with Azoles and Benzoazoles: A Novel Simple Approach for Synthesis of 3‐Functionally Substituted 3‐Acylindoles.

Abstract

Substituted 3-Acylindoles. -Carboxylic acids in the presence of acetic anhydride acylate indole regioselectively at the C-3 position. Moreover, chloroacetyl chloride reacts directly. The 3-functionalized products are excellent precursors for the synthesis of biologically interesting azolyl indoles [cf. (VII)] that are otherwise difficult to access. -(ABDEL-MOTALEB, R. M.; MAKHLOOF, A.-M. A.-S.; IBRAHIM, H. M.; ELNAGDI*, M. H.; J. Heterocycl. Chem. 44 (2007) 1, 109-114; Dep. Chem., Fac. Chem., Cairo Univ., Giza, Egypt; Eng.) -R. Staver 23-108

Acylation of Heteroaromatic Amines: Facile and Efficient Synthesis of a New Class of 1,2,3-Triazolo[4,5-b]pyridine and Pyrazolo[4,3-b]pyridine Derivatives

“…We have previously [ 10 ] suggested that in the mechanistic pathway for the process described by Slatt [ 9 ], the mixed anhydride is formed initially and then it reacts by nucleophilic addition of an amine or electron rich aromatic system at the more electron deficient cyanoacetyl carbonyl. As a consequence of this proposal, we believed that other mixed anhydrides could be used as arylacetamide precursors provided that the reactions occur at the more electron deficient aroyl carbonyl.…”

“…The present study describes the results of an investigation aimed at the preparation of a new class of 1,2,3-triazolo[4,5- b ]pyridine and pyrazolo[4,3- b ]pyridine derivatives. Cyanoacetylation of electron rich aromatic compounds and heteroarmatic amines, initially described by Slatt et al , [ 9 ] has found extensive utility in efficient routes for the preparation of 3-oxoalkanonitriles [ 10 , 11 , 12 , 13 , 14 , 15 ] and cyanoacetamides [ 16 , 17 , 18 ]. Cyanoacetylation of o -acyl heteroarmatic amines is expected to give cyanoacetamides in which an active methylene moiety is located in close proximity to a ketone carbonyl function.…”

Synthesis and antimicrobial evaluation of some new hydrazo, dihydropyridazinyl and triazolyl derivatives containing indole nucleus

“…> 249°C (Lit. Abdel-Motaleb et al , 2007, m.p. 251°C); IR (KBr): ν max (cm −1 ): 3,237, 3,441 (2NH stretching), 2,215 (CN), 1,640 (C = O, stretching), 1,517 (C = N); 1 HNMR (DMSO-d6): δ (ppm): 6.99-7.59 (m, 9H, Ar-H), 8.24 (s, 1H, CH-indole ring), 11.89 (s, 1H, NH), 12.00 (s, 1H, NH); 13 C NMR (DMSO-d6): δ (ppm): 110.4, 110.6, 111.0, 113.4, 115.3, 119.0, 119.4, 121.7, 121.8, 122.4, 129.4, 129.5, 137.0, 138.0, 143.0, 193.3; MS (EI,70 eV): m/z (%) = 288 (M + , 43), 271 (47), 144 (76), 117 (28), 116 (47), 103 (6), 102 (5), 92 (19), 90 (15), 89 (48), 77 (66).…”

An easy synthesis of 5-functionally substituted ethyl 4-amino-1-aryl- pyrazolo-3-carboxylates: interesting precursors to sildenafil analogues

“…The reported synthetic approaches to these derivatives are also multistep, non atom economical and non eco friendly [1,5,6]. Recently however a route to 4-aminopyrazole-5-carboxylic acid derivatives via reacting 2-arylhydrazononitriles with α-haloacid derivatives has been reported by Elnagdi et al [7,8] as well as other researchers [9]. In the present article we report results of our work aimed at exploring this synthetic methodology and adoption of products for the synthesis of pyrazolo[4.3- d ]pyrimidines.…”