Significance of reagent addition sequence in the amidation of carboxylic acids mediated by PPh₃ and I₂

Abstract

The outcome of the amidation reaction mediated by PPh3–I2 was found to be highly dependent on the addition sequence of the reagents.

A high‐efficient method for the amidation of carboxylic acids promoted by triphenylphosphine oxide and oxalyl chloride

“…The product (0.93 g, 94% yield) was obtained as a yellow solid; mp 161‐162°C [Wangngae et al . 162‐163°C]; 1 H NMR (500 MHz, CDCl 3 ): δ 7.90 (d, J = 7.4 Hz, 2H), 7.84 (s, 1H), 7.67 (d, J = 7.9 Hz, 2H), 7.58 (t, J = 7.3 Hz, 1H), 7.52 (t, J = 7.5 Hz, 2H), 7.40 (t, J = 7.8 Hz, 2H), 7.18 (t, J = 7.4 Hz, 1H); 13 C NMR (125 MHz, DMSO): δ 166.0, 139.6, 135.4, 132.0, 129.2, 129.0, 128.8, 128.1, 124.1, 120.8, 114.3, 40.5, 40.3, 40.1, 40.0, 39.8, 39.6, 39.5; HRMS (FT ICR‐MS) m/z: [M+H] + calcd for C 14 H 13 NO 198.091340; found 198.09106.…”

“…The product (0.87 g, 86% yield) was obtained as a white solid; mp 143.4‐143.9°C [Wangngae et al . 143‐144°C]; 1 H NMR (500 MHz, CDCl 3 ): δ 7.77 (d, J = 7.3 Hz, 2H), 7.51 (t, J = 7.3 Hz, 1H), 7.45 (t, J = 7.4 Hz, 2H), 5.97 (s, 1H), 4.12‐3.89 (m, 1H), 2.06 (d, J = 9.4 Hz, 2H), 1.78 (d, J = 13.4 Hz, 2H), 1.68 (d, J = 12.9 Hz, 1H), 1.46 (dd, J = 25.0, 12.4 Hz, 2H), 1.34‐1.24 (m, 3H); 13 C NMR (125 MHz, CDCl 3 ): δ 166.6, 135.1, 131.2, 128.4, 126.8, 48.7, 33.2, 25.5, 24.9; HRMS (FT ICR‐MS) m/z: [M+H] + calcd for C 13 H 17 NO 204.138291; found 204.13761.…”

“…The product (0.96 g, 94% yield) was obtained as a white solid. mp 103.4-104.4°C [Wangngae et al [61]…”

A new methodology for the synthesis of N-acylbenzotriazoles

“…32 The intermediate (A) reacts with carboxylic acid to form acyloxyphosphonium ion 33 with the loss of succinimide. This acyloxyphosphonium ion (B) further reacts with BtH to form the final product N-acylbenzotriazole 2.…”

Ultrasonic-assisted synthesis of carbodiimides from N,N′-disubstituted thioureas and ureas

“…In continuation of our study involving the Ph 3 P-I 2 reagent system [43][44][45][46], herein we wish to report a facile and effective sonochemical method for the synthesis of carbodiimides from thioureas and ureas using the Ph 3 P-I 2 system.…”