发明授权
US4384094A 3-Substituted- 7-dialkylamino-spiro(2H-1-benzopyran-2,3'-(3H)-naphtha(2,1-b)pyrans) 失效
3-取代的7-二烷基氨基螺(2H-1-苯并吡喃-2,3' - (3H) - 萘(2,1-b)吡喃)

3-Substituted-
7-dialkylamino-spiro(2H-1-benzopyran-2,3'-(3H)-naphtha(2,1-b)pyrans)
摘要:
Substituted spiro 2H-1-benzopyran-2,3'-(3H)-naphtho(2,1-b)pyrans particularly suitable for use as precursors to stable colored pyrylium salts are disclosed.
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