1-Naphthylhydrazine hydrochloride synthesis

Yield: 63%

Reaction Conditions:

Stage #1:naphthalen-2-ylamine with hydrogenchloride;sodium nitrite in water at 0; for 1 h;
Stage #2: with tin(ll) chloride in water at 0; for 3.5 h;

Steps:

2.1; 4.1
2.1 Synthesis of 2-naphthylhydrazine hydrochlorideNaN0₂ (578 mg, 8.38 mmol) in H₂0 (1 .2 mL) was slowly added (2 min of addition) over a suspension of 2-naphthylamine (800 mg, 5.59 mmol) in HCI ac. 6.0 M (6 mL) cooled in a H₂0-ice bath. The resulting solution was stirred in H₂0-ice bath for 1 h, and SnCI₂ (3.71 g, 19.56 mol) was added slowly (5 min of addition). The resulting suspension was stirred in H₂0-ice bath for 3.5 h, and then filtered. The solid was successively washed with H₂0 at 0 °C (4x8 mL), with H₂0 at rt (1 x8 mL), with Et₂0 at 0 °C (2x4 mL), with Et₂0/hexane (1 :1 , 2x4 mL) and with hexane (2x5 mL). The solid was dried to yield 690 mg of the desired product {Rf= 0.7 (40% AcOEt/hexane), cream solid, 63% yield). NMR-¹H (DMSO-de, 250 MHz, δ): 7.81 (m, 2H, ArH); 7.71 (d, J7.49-7.19 (m, 4H, ArH).MS-EI+ m/z: 159.1 (M-HCI+1 ).

References:

LABORATORIOS DEL DR. ESTEVE, S.A.;GARCÍA LÓPEZ, Mónica;TORRENS JOVER, Antoni;DÍAZ FERNÁNDEZ, José Luis;CAAMAÑO MOURE, Ana María WO2011/147910, 2011, A1 Location in patent:Page/Page column 29-30; 36-37