Reaction #487551

Reaction equation

4-chloro-N-(5-phenyl-1,3,4-thiadiazol-2-yl)butanamide

piperidine

water

→

crude product

2-Phenyl-6,7-dihydro-[1,3,4]thiadiazolo[3,2-α][1,3]diazepin-8(5H)-one

Solvents

toluene

Conditions

Workup

1. 1
   Temperaturewas heated
2. 2
   Temperatureunder reflux for 3 h
3. 3
   TemperatureThe reaction mixture was cooled
4. 4
   OtherToluene was separated
5. 5
   Otherdried
6. 6
   Otherevaporated

Procedure

A mixture of 4-chloro-N-(5-phenyl-1,3,4-thiadiazol-2-yl)butanamide (1.1 g, 0.004 mol) and piperidine (0.7 g, 0.8 ml, 0.008 mol) in toluene (50 ml) was heated under reflux for 3 h. The reaction mixture was cooled, poured into water and stirred. Toluene was separated dried and evaporated to give a crude product which was purified by repeated silica gel and neutral alumina column chromatography eluting with EtOAc/hexane (50:50 v/v) and CHCl3/hexane (80:20 v/v); mp 189-92° C., m/e 245, 90% (consistent with molecular formula C12H11N3OS, calcd. 245.06) 1H NMR CDCl3): δ 2.33-2.36 (m, 2H, —CH2), 2.75 (t, J=7.5 Hz, 2H, —CH2), 4.28-4.31 (t, J=7.5 Hz, 2H, —CH2), 7.46-7.52 (m, 3H, ArH), 7.94-8.10 (m, 2H, ArH). 13C NMR: δ 18.3, 31.3, 47.9, 127.4, 129.1, 130.5, 130.6, 157.4, 163.9, 173.6.

Source