Benzopyrans. Part 30. Synthesis of substituted xanthones from 3-acyl-2-methyl-1-benzopyran-4-ones
作者:Chandra Kanta Ghosh、Sirin Sahana、Amarendra Patra
DOI:10.1016/s0040-4020(01)89924-5
日期:1993.5
The xanthone 8 results from the base catalysed self-condensation of the chromone 1. The chromone 2 gives the xanthones 9 and 11 with sodium and DMF-POCl3 respectively, phenol 14 with NaOMe, and the pyran 22 with 2-thiomethylchromone 6. The enamine 16 on Vilsmeier-Haak reaction affords the chloroxanthone 12. The pyran 15, isolated as a byproduct from the reaction of ω-acetyl-2-hydroxyacetophenone with
Conjugate addition of cuprate reagents to chromones: A route to 2-substituted chroman-4-ones
作者:Suthiweth T. Saengchantara、Timothy W. Wallace
DOI:10.1016/s0040-4020(01)88394-0
日期:1990.1
Chromones (4-oxo-4H-1-benzopyrans) activated by electron-withdrawing groups attached to C-3 undergo efficient 1,4-additon of cuprate reagents, producing 2,3-disubstituted chroman-4-ones. The addition products from methyl chromone-3-carboxylates can be converted into 2-substitutedchroman-4-ones by treatment with sodium chloride in wet dimethylsulphoxide.
Domino reactions of 2-methyl chromones containing an electron withdrawing group with chromone-fused dienes
作者:Jian Gong、Fuchun Xie、Wenming Ren、Hong Chen、Youhong Hu
DOI:10.1039/c1ob06613g
日期:——
Domino reactions of 2-methyl substituted chromones containing an electronwithdrawinggroup at the 3-position with chromone-fused dienes synthesized a diverse range of benzo[a]xanthones and complicated chromone derivatives. These multiple-step reactions result in either two or three new C–C bonds without a transition metal catalyst or an inert atmosphere.
在3位上具有吸电子基团的2-甲基取代的色酮与色酮稠合的二烯的多米诺反应合成了多种苯并[ a ]氧杂蒽酮和复杂的色酮衍生物。这些多步反应可产生两个或三个新的C–C键,而无需过渡金属催化剂或惰性气氛。
Novel merocyanine dyes are converted into the spiropyran form by irradiation with visible light
MATERIALS FOR OPTICAL MEDIUM COPY-PROTECTION TRANSIENTLY REACTING TO A READER BEAM
申请人:SELINFREUND H. Richard
公开号:US20080062838A1
公开(公告)日:2008-03-13
A method and system for providing copy-protected optical medium using transient optical state change security materials capable of changing optical state and software code to detect such change in optical state.