Reaction Steps
To a stirred solution of t-butyl nitrite (271 mg, 0.312 ml, 2.63 mmol) in DMF (15 ml) at 60°-65° C. was added 7-allyloxy-3-amino-1,2,4-benzotriazine-1,4-dioxide 23 (205 mg, 0.875 mmol) in small portions over 5 min. After 30 min additional t-butyl nitrite (271 mg, 0.312 ml, 2.63 mmol) was added, and shortly thereafter the deep red solution effervesced and lightened appreciably in color over a period of a few minutes. After an additional 30 min the resultant orange solution was reduced under vacuum to a brown solid which was sequentially flash chromatographed (10% EtOAc/CH2Cl2) and crystallized (CH2Cl2 /petroleum ether) to give 72 mg (38% yield) of the product 24 as light orange crystals, mp 147°-148° C. NMR: δ (400 MHz, d6 -acetone) 4.89 (2H, ddd, H-1', J1',2' =5.5, J1',3'cis =J1',3'trans =1.5 Hz), 5.36 (1H, ddd, H-3', J3',2'cis =10.5, J3',3' =3, J3',1' =1.5 Hz), 5.52 (1H, ddd, H-3', J3',2'trans =17.5, J3',3' =3, J3'1' =1.5 Hz), 6.14 (1H, ddt, H-2', J2',3'cis =10.5, J2',1' =5.5 Hz), 7.70 (1H, d, H-8, J8,6 =2.5 Hz), 7.74 (1H, dd, H-6, J6,5 =9.5 J6,8 =2.5 Hz), 8.33 (1H, d, H-5, J5,6 =9.5 Hz), 8.93 (1H, s, H-3). UV: λ 425, 410, 365, 355, 320, 245, 200. MS m/z/(relative intensity) 220(4), 219(34,M+),103(4), 77(4), 75(4), 63(13), 62(4), 42(3), 41(100), 39(16).
