mole di tert butyldicarbonate 4 3 g 0 02 mole and triethulamine tea 2 02 g 0 02 mole in 100 ml dry tetrahydrofyran thf which was passed through al 2 o 3 basic was allowed to stand overnight at room temperature the thf and tea were evaporated and the oily residue was dissolved in 50 ml of ch 2 cl 2 the solution was extracted 3 u00d7 50 ml 5 ch 3 cooh to take out the boc amino fisher 39 s base ii in the form of its quaterney acetate salt the water fraction with salt was washed 2 u00d7 50 ml ether and made alkaline ph 9 10 with cooling and stirring the white precipitate was extracted 3 u00d7 50 ml ch 2 cl 2 dried with mgso 4 filtered and then the solvent was evaporated to give 5 35 g 93 of very viscous oil ii rapidly becoming reddish this product was used directly in the following step without further purification 5 amino n tert butyloxycarbonyl 1 3 3 trimethyl 6 39 nitrospiro indoline 2 2 39 2h 1 benzopyran boc amino spiropyran iii heinnen a audic c gautron r bull soc chim france 5 2066 2074 1968 a mixture of boc amino fischer 39 s base 5 35 g 0 018 m and 5 nitrosalicylaldehyde 3 1 g 0 018 mole in 100 ml of methanol analytical was refluxed for 0 5 h the brilliant green precipitate was separated and washed with cold methanol after recrystallization from hexane benzene 1 2 the yield of yellow crystals iii was 6 3 g 78 5 amino 1 3 3 trimethyl 6 39 nitrospiro indoline 2 2 39 2h 1 benzopyran amino spiropyran iv lundt b f johansen n l.