Seven-membered heterocycle-containing

Three-, five-, six- and seven-membered heterocycles containing one sulfur atom, except for those described above, can be obtained from various organic substances and sulfur monochloride. 

Seven-membered heterocycles containing one nitrogen atom may be obtained either from 105 (see p. 376) or 6-amino-6-deoxy-D-glucose (227) by reduction122 to 228, or from 6-azido-6-deoxy-D-glucopyranose (229) by oxidation to 230 followed by reduction of 230 to 231. A... 

The non-planar polyene nature of azepines renders them susceptible to a variety of intra-and inter-molecular pericyclic processes. The azepine-benzeneimine valence isomerization has been discussed in Section 5.16.2.4, and the ring contractions of azepines to benzenoid compounds in the presence of electrophiles is covered in Section 5.16.3.3. In this section the thermal and photochemical ring contractions of azepines to bicyclic systems, their dimerizations and their isomerizations via sigmatropic hydrogen shifts are discussed. Noteworthy is a recent comprehensive review which compares and contrasts the many and varied valence isomerizations, dimerizations and cycloadditions of heteroepins (conjugated seven-membered heterocycles) containing one, two and three heteroatoms (81H(15)1569). 

Seven-membered heterocycles containing at least two heteroatoms ... 

To date there have been found only cularine and several of its 0- or N-desmethyl derivatives. The unique feature of this group is the presence of a seven-membered heterocycle containing an oxygen atom in a diphenyl ether linkage. The known occurrence of these alkaloids is restricted to the genera Dicentra and Corydalis. 

The synthesis and use of seven-membered heterocycles containing three heteroatoms N, O, and/or S, has been the focus of a number of publications in 2014. In all but one report the heterocycle contains three heteroatoms,... 

Since this topic was last reviewed, " a book on seven-membered heterocycles containing oxygen and sulphur has been published. ... 

Dipolarophiles utilized in these cycloadditions leading to five-membered heterocycles contain either double or triple bonds between two carbon atoms, a carbon atom and a heteroatom, or two heteroatoms. These are shown in Scheme 9 listed in approximate order of decreasing activity from left to right. Small rings containing a double bond (either C=C or C=N) are also effective dipolarophiles, but these result in six- and seven-membered ring systems. 

A synthetically useful application of an intramolecular microwave-assisted Heck reaction has been described by Gracias and coworkers (Scheme 6.9) [28], In their approach toward the synthesis of N-containing seven-membered heterocycles, the... 

However, intramolecular O-alkylation can be performed under particular conditions leading to of annelation of a seven-membered heterocycle. Japanese researchers (170) prepared the corresponding seven-membered cyclic nitronates (50a-c) in good yields by the reaction of triethylamine with brominated aryl ketones (49a-c) containing the nitromethyl group in the ortho position. 

The protocol mentioned above for the preparation of dihydropyrans was also applied to the amidopalladation of allenes 8 and the subsequent RCM of N,0-acetal intermediates 216. This method leads to the expected five-, six- and seven-membered nitrogen-containing heterocycles 217 with good efficiency (Scheme 8.53) [118a],... 

Nonphenolic oxidative coupling of phenol ether derivatives using IBTA can also produce seven-membered N-containing heterocyclic compounds as exemplified by Eq. (45) [96JCS(CC)1481],... 

Mercaptoacids were successfully applied in the MRCs with aminozoles on the way to the novel sulfur containing seven-membered heterocycles [145-147], Thus, condensation of 5-aminopyrazoles with mercaptoacetoacid and aromatic ketones or aldehydes resulted in the formation of pyrazolothiazepines 107 (Scheme 50). 

The basic chemical structure of the benzodiazepines consists of a benzene ring coupled to a seven-member heterocyclic structure containing two nitrogens (di-azepine) at positions 1 and 4 (Fig. 30.1). Of the 2,000 benzodiazepines that have been synthesized, approximately 15 clinically useful compounds are on the market in the United States (Table 30.1). 

Murai and co-workers report that moderate yields of six- or seven-membered nitrogen-containing heterocycles result from the reaction of acetylene hydrazones with HSiMe2 Bu and CO in the presence of catalytic amounts of Ir4(CO)12 [Eq. (54)].134... 

Seven-membered nitrogen-containing heterocycles, especially those fused to benzene rings, are important in drug design. The famous tranquillisers Librium 91 and Valium are based on... 

A seven-membered heterocycle is formed from the bicyclic heterocycle initially produced by the reaction of fluorine-containing cyclobutene with diazomethane due to a rearrangement leading to a high yield of the product (83JCS(CC)5). 

A. Rosowsky (ed.) Seven-membered Heterocyclic Compounds Containing Oxygen and Sulfur, Chem. Heterocycl. Compd., Vol. 26, Wiley (Interscience), New York, 1972. 

Seven-, eight-, and nine-membered heterocycles containing nitrogen, oxygen, and phosphorus atoms 288 were prepared by the reaction of phosphonic dichlorides with corresponding amino alcohols 287. Obtained esters 288 were converted into hydroxamic acids 289 upon treatment with NaOMe and 0-(trimethylsilyl)hydroxylamine <2003BMC5461>. 

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