Two new series of 1,3-dihydrospiro[2H-indole-oxazine] derivatives were synthesized, the 1,3-dihydrospiro[ZHindole-2,3'-[3H]pyrimido[5,4-fl[l,4]benzoxazines] 4 10 and the 1,3-dihydrospiro[2H-indole-2,7'-[7H]thiazolo-[5,4-f~[1,4]benzoXdzines] 11-17. These series extend the available range of photochromic properties (rate constant of thermal bleaching, UVjVIS spectrum of the opened coloured form, and photocoloration yield), an interesting feature of variable-transmission materials. The synthesis of these compounds (Scheme I ) required the preliminary synthesis of intermediate p-hydroxy-r -nitrosoheterocycles 18 and 19 (Scheme 2). Important amounts of a coloured, non-photochromic, stable secondary product (see 20) were formed in the condensation in the spiro-[indole-thiazolobenzoxazine] series. The photochromic characteristics of the new derivatives were determined using a flash-photolysis apparatus coupled to a fast-scanning spectrometer. The role of the heteroatoms in the oxazine moiety and the role of substituents in the indole moiety were investigated quantitatively through the study of the photochromic properties and the solvent effects. The presence of an S-atom gives rise to interesting properties which open up new prospects for synthesis and applications. 1. Introduction. ~ En 1961 Fox [l] a le premier signale une nouvelle famille de composes photochromes organiques proches structuralement des spiropyranes A: les spirooxazines B dont l'originalitk rkside dans le remplacement du pont etheno CH(2')=CH(l') par un pont imino CH(2')=N( 1').
A spiro[indole-naphthopyrane] B spiro[indole-naphthoxazine] Entre 1961 et 1980, les spirooxazines ont suscite peu d'intkret, et seuls quelques brevets de synth2se sont apparus dans la litterature [2] [3]. Chu [4a] [5] est alors le premier a mettre en evidence la remarquable resistance a la photodkgradation de ces composts qui laisse entrevoir un potentiel intkressant dans le domaine des filtres solaires. Depuis 1980, 4