Phosphorus sulfide (P2S5) → 8-Quinolinecarbonitrile, 5,6,7,8-tetrahydro-2-phenyl-
Reaction equation
[C:1]1([C:7]2[CH:16]=[CH:15][C:14]3[CH2:13][CH2:12][CH2:11][CH:10]([C:17]([NH2:19])=O)[C:9]=3[N:8]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.P12(SP3(SP(SP(S3)(S1)=S)(=S)S2)=S)=S>N1C=CC=CC=1>[C:17]([CH:10]1[C:9]2[N:8]=[C:7]([C:1]3[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=3)[CH:16]=[CH:15][C:14]=2[CH2:13][CH2:12][CH2:11]1)#[N:19]Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
2-Phenyl-5,6,7,8-tetrahydroquinoline-8-carboxamide (8 g.) was dissolved in pyridine (20 ml.), treated with P2S5 (5.2 g.) and the mixture heated at reflux temperature for 30 minutes. The solvent was removed in vacuo and the residual oil dissolved in dilute HCl, washed with ether (2 × 50 ml.) and the washings discarded. The aqueous solution was made basic, extracted into chloroform (3 × 50 ml.) and the combined extracts dried and evaporated to dryness. The residual oil was chromatographed on silica gel by elution with chloroform giving 8-cyano-2-phenyl-5,6,7,8-tetrahydroquinoline (1.2 g.) as colourless needles from ether mpt. 100° C. Found: C, 82.0; H, 6.2; N, 11.7% C16H14N2 requires: C, 82.0; H, 6.0; N, 11.9%. Further elution with chloroform gave the title compound (1.1 g.) as colourless needles from ether mpt. 154° C. Found: C, 71.8; H, 6.1; N, 10.2 %, C16H16N2S requires: C, 71.6; H, 6.0; N, 10.4%.