Biological activity tetrahydro

Cannabinol, A -3,4-trans-tetrahydro-biological activity, 3, 877 Cannabinol, (—)-A -3,4- ran5-tetrahydro-as pharmaceutical, 1, 151 Cannabinolic acid synthesis, 3, 721 Cannabinolic acid, tetrahydro-photochemistry, 3, 721 Cannabis, citrylidene-, 3, 675 Cantharidin synthesis, 1, 440 Capillarin occurrence, 3, 677 ozonolysis, 3, 681... 

Folic acid, 4-amino-4-deoxy-10-methyl-, 1, 164 3, 325 as anticancer drug, 1, 263 biological activity, 3, 325 Folic acid, 4-amino-10-methyl-toxicity, 1, 141 Folic acid, 7,8-dihydro-biosynthesis, 3, 320 synthesis, 1, 161, 3, 307 Folic acid, 4-dimethylamino-hydrolysis, 3, 294 Folic acid, 5-formiminotetrahydro-biological activity, 3, 325 Folic acid, 5-formyl-5,6,7,8-tetrahydro-biological activity, 3, 325 chirality, 3, 281 occurrence, 3, 325 Folic acid, 10-forfnyltetrahydro-biological activity, 3, 325 Folic acid, 5,10-methenyl-5,6,7,8-tetrahydro-biological activity, 3, 325 chirality, 3, 281 Folic acid, 5-methyl-chirality, 3, 281 Folic acid, 9-methyl-toxicity, 1, 141... 

Folic acid, 5,10-methylene-5,6,7,8-tetrahydro-biological activity, 3, 325 chirality, 3, 281... 

Folic acid, 5-methyltetrahydro-biological activity, 3, 325 oxidation, 3, 308 Folic acid, iV-nitroso-carcinogenicity, 1, 141 Folic acid, 10-oxa-synthesis, 3, 327 Folic acid, 4-piperidyl-hydrolysis, 3, 294 Folic acid, 5,6,7,8-tetrahydro-chirality, 3, 281 synthesis, 1, 161 Folic acid, 10-thio-synthesis, 3, 327... 

Homofolic acid, 5,11-methenyl-tetrahydro-biological activity, 3, 327 Homofolic acid, tetrahydro-biological activity, 3, 327 Homoisoflavanones occurrence, 3, 722 thermoisomerization, 3, 722 thermolysis, 3, 728 Homolytic reactions heterocyclic compounds reviews, 1, 74 Homophthalic acid isocoumarins synthesis from, 3, 830 synthesis, 3, 830 Homophthalic anhydride isochroman-l-one synthesis from, 3, 860 20a-Homoporphyrin nomenclature, 1, 30 Homopterocarpin isolation, 4, 998 ( )- D- Homotestosterone synthesis, 1, 453 Homer-Emmons reaction chromene synthesis by, 3, 749 Hortiacine isolation, 3, 149 Hortiamine isolation, 3, 149... 

Thieno[2,3-c]pyridine, 2-amino-6-benzyl-3-ethoxycarbonyl-4,5,6,7-tetrahydro-biological activity, 4, 1015 Thieno[2,3-c]pyridine, 4,5,6,7-tetrahydro-biological activity, 4, 1015 Thieno[3,2-6]pyridine, 3-hydroxy-synthesis, 4, 1010... 

According to Urbanski et al. biological activity of 1,3-oxazine derivatives is due to the active CH2 group in the 2-position. Tne use of tetrahydro-l,3-oxazines was also suggested against some infections in veterinary service. The suggested use of tetrahydro-l,3-oxa-zines as herbicides did not seem to be a success. 

In his approach toward selenium-containing heterocycles with potential biological activity, Abdel-Hafez reacted 2-amino-3-(4,5-dihydro-17/-imidazol-2-yl)-4,5,6,7-tetrahydro-l-benzoselenophene 297 with triethyl orthoformate and benzaldehyde to generate the tricyclic systems 296 and 298, respectively (Scheme 21) <2005RJ0396>. Similarly, reaction with carbon disulfide gave the corresponding thiourea 299. 

Pyrrolo[l,2-A]thiazoles are aromatic compounds but only one fully conjugated derivative has been described. A few dihydro and tetrahydro derivatives have been prepared, mainly in connection with search for biologically active drugs. Saturated compounds are also known. 

The most widely used route to l-benzazepin-2-ones involves the Beckmann or Schmidt reaction of the easily accessible 1-tetralones. Many biologically active compounds described in this review have been prepared on the basis of these reactions they have been fully reviewed [2], In the Beckmann reaction of 1-tetralone oximes, polyphosphoric acid is used as a catalyst-solvent in most instances. Aryl migration generally takes precedence over alkyl migration under these reaction conditions, and various 1-tetralone oximes substituted on the aromatic and/or aliphatic rings can be converted to the appropriate 2,3,4,5-tetrahydro-l//-l-benzazepin-2-ones (51) [5, 20-23, 36, 59, 65, 80, 107-112]. Both courses of the rearrangement occur in some instances, yielding l-benzazepin-2-ones (51) and the isomeric 2-benzazepine-l-ones, probably due to electronic effects of the substituents [90, 113, 114]. 

The Pictet-Spengler reaction is the method of choice for the preparation of tetrahydro-P-carbolines, which represent structural elements of several natural products such as biologically active alkaloids. It proceeds via a condensation of a carbonyl compound with a tryptamine followed by a Friedel-Crafts-type cyclization. In 2004, Jacobsen et al. reported the first catalytic asymmetric variant [25]. This acyl-Pictet-Spengler reaction involves an N-acyliminium ion as intermediate and is promoted by a chiral thiourea (general Brpnsted acid catalysis). 

The biologically active relatives of folic acid and biopterin are the tetrahydro compounds with a reduced pyrazine ring. Reduction to this level occurs rapidly in vivo. The corresponding electrochemical process is well illustrated by reduction of the N-methylated analogue 28 [95], Reduction to the 5,8-dihydro stage is a reversible two-electron and two-proton process. The product rapidly tautomerises to the... 

Table VII lists biological activities that have been found for some aromatic azapentalenes. Among these, imidazo[2,l-6]thiazoles have probably been most studied, and this has partly followed the discovery454 that a tetrahydro derivative 480 possessed marked anthelmintic activity. This compound is marketed as Tetramisole (or as the L-isomer, Levamisole) and is at present one of the most effective agents for the treatment of roundworm infestations. Anthelmintic activity has been found for aromatic imidazo[2,l-6]thiazoles (Table VII), and it has been suggested331 that a 6-aryl substituent is necessary for activity in this series.

Both tetrahydro-l,4-oxazine (morpholine) and its thia analogue (thiomorpholine) find application as solvents and bases, morpholine having particular value in synthesis as it is often used to prepare enamines from ketones with a free a-hydrogen atom. TV-Acylation and -alkylation are readily accomplished and a great diversity of TV-substituted morpholines and thiomorpholines are encountered in the patent literature, some having biological activity. 

Tetrahydro derivatives, such as compounds 156-158, some possessing biological activity, have been prepared by the routes shown in Eqs. (20)-(22).216-219 Another compound with a reduced pyrrole ring is the product obtained from the reaction of Ar-methyl-2-pyridone with maleic anhydride, formulated as the (unlikely) structure 159. It is very labile, dissociating to Ar-methyl-2-pyridone and maleic acid in polar solvents.220... 

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