摘要:

AbstractAll‐E‐12,19‐methanoretinal (1) is distinguished by the presence of the locked 10‐s‐cisconformation in the cyclohexadiene ring in the conjugated chain.1has been prepared together with its 13‐Z isomer in an overall yield of 0.5%.1and 13‐Z‐1photochemically interconvert in a clean way. In this system, only photoisomerization around the C13  C14 double bond is observed. In the photostationary state, the 13‐Z isomer is predominant. All‐E‐12‐ethyl‐19‐methylretinal (2) and all‐E‐12‐ethylretinal (3) were prepared in good overall yields (20% and 30%) from β‐ionone using the novel synthon, 3‐methyl‐4‐(diethylphosphono)‐2‐hexenenitrile (11). The photochemistry of these retinal derivatives is very similar to that of retinal. The 9‐Z, 11‐Z and 13‐Z isomers of2and3were photochemically prepared. The13C NMR spectra of these new compounds gave information about the structural elements of alkyl groups in conjugated syst

ISSN:0165-0513    

DOI:10.1002/recl.19891081202

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractA convenient synthesis of three cyclopenta[ad]pyrene derivatives methylated on the five‐membered ring is described. The starting materials were easily available ketones which were either Wolff‐Kishner‐reduced or treated with methyllithium followed by dehydration withp‐toluene‐sulfonic acid to give the partially saturated derivatives. Careful aromatization with DDQ gave the novel methylated compounds in reasonab

ISSN:0165-0513    

DOI:10.1002/recl.19891081203

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractA new route for the synthesis of 1,3‐disubstituted indoles, based on (N‐arylaminomethyl)‐diphenylphosphine oxide (1) chemistry, is described. Adducts2, obtained by addition of the carbanions from1to aldehydes, were treated withp‐toluenesulfonic acid to form the desired indoles 4 in good yields, without isolation of the intermediate amino ke

ISSN:0165-0513    

DOI:10.1002/recl.19891081204

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe sulfation and sulfonation of a series of mono‐, di‐ and trimethyl ethers of the trihydroxybenzenes with SO3have been studied and the product distributions are reported. As for the trimethoxybenzenes, 1,2,3‐trimethoxybenzene (4) yields the 4‐sulfonic acid (4‐4‐S) and, upon further sulfonation, 4‐4,6‐S2. 1, 2, 4‐Trimethoxybenzene (7) yields a mixture of the 5‐sulfonic acid and its anhydride. 1, 3, 5‐Trimethoxybenzene (11) yields the 2‐sulfonic acid and, upon further sulfonation,11‐2,4‐S2.1, 2‐Dihydroxy‐3‐methoxybenzene (1) with up to 2.0 equiv of SO3yields the 6‐sulfonic acid. For 2, 6‐dimethoxyphenol (2), the ratio of 3‐ to 4‐sulfonation increases from 1.04 to 7.1 on using 4.0 instead of 0.9 equiv of SO3, due to initial formation of the hydrogen sulfate derivative and subsequent ring sulfonation of that species. 3,4‐Dimethoxyphenol (5), upon sulfonation with both 1.0 and 4.0 equiv of SO3, only yields the 6‐sulfonic acid. 1,3‐Dihydroxy‐5‐methoxybenzene (8), upon sulfonation with 1.0 equiv of SO3, yields8‐2‐S and8‐4‐S in a 1:1 ratio in addition to 20% of the hydrogen sulfate of8. Upon further reaction, a mixture of 8‐2,4(= 2,6)‐S2and 8‐4,6‐S2is formed. 3,5‐Dimethoxyphenol (9), upon reaction with 1.0 equiv of SO3, yields9‐2‐S, whereas with 4.0 equiv of SO3, a 32:68 mixture of9‐2‐S,9‐4‐S is obtained. The reactions with SO3of three dimethoxyphenyl methanesulfonates, as model compounds for the corresponding hydrogen sulfates, which are the initial products formed by sulfation of the corresponding phenols, have also been studied. The observed sulfonic acid

ISSN:0165-0513    

DOI:10.1002/recl.19891081205

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe fluorescence of Fluoroprobe, a molecule with an extremely polar excited state, is studied in matrices consisting of (macro)molecules which contain repeating units of different polarity. In matrices of low molecular weight Fluoroprobe displays its typical bathochromic shift with increasing contribution of polar groups, but an hypsochromic shift is observed in viscous or solid matrices of high molecular weight. This remarkable phenomenon is attributed to loss of mobility, which allows fluorescence of the probe to occur prior to full relaxation of the surrounding matrix sites.

ISSN:0165-0513    

DOI:10.1002/recl.19891081206

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19891081208

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19891081209

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19891081210

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19891081201

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY