Γ-Lakton-cis-anellierung an Δ2- und Δ3- Cholesten

γ-Lactone-cis-annulation to Δ²- and Δ³- Cholestene. From Δ²- and Δ³- cholestene the γ-lactones 11a , 11b , 12a , and 12b are synthesized through the dibromocarbene adducts 3 and 4 , the bromohydrines 5 and 6 , the oxapiropentanes 7 and 8 , and the cyclobutanones 9a , 9b and 10a , 10b , respectively. The ¹³C-NMR.-spectra of 1–8 and 11 as well as the ORD.-spectra of the cyclobutanones 9 and 10 are reported.     

Δ3- and Δ4-1,2,4-oxadiazolin-5- and 3-ones

Preparations for 2,3-diphenyl- and 2-benzyI-3-phenyl-Δ³-1,2,4-oxadiazolin-5-ones (3) and (4) and for 2,5-diphenyl-Δ⁴-1,2,4-oxadiazolin-3-one ( 7 ) are reported.     

5-(α-Fluorovinyl)tryptamines and 5-(α-Fluorovinyl)-3-(N-methyl-1′,2′,5′,6′,-tetrahydropyridin-3′- and -4′-yl)indoles—5-(α-Fluorovinyl)tryptamines

5-(α-Fluorovinyl)tryptamines 4a, 4b and 5-(α-fluorovinyl)-3-(N-methyl-1′,2′,5′,6′-tetrahydropyridin-3′- and -4′-yl) indoles 5a, 5b were synthesized using 5-(α-fluorovinyl)indole ( 7 ). The target compounds are bioisosteres of 5-carboxyamido substituted tryptamines and their tetrahydropyridyl analogs.     

3′-(1,2,3-Triazol-1-yl)-2′,3′-dideoxythymidine and 3′-(1,2,3-triazol-1-yl)-2′,3′-dideoxyuridine

Cycloaddition of different acetylenic compounds on the azido function of 3′-azido-2′,3′-dideoxythymidine and 3′-azido-2′,3′-dideoxyuridine afforded products with a 1,2,3-triazol-1-yl substituent in the 3′-position. In contrast with the parent compounds, these triazolyl derivatives had no appreciable activity against human immunodeficiency virus (HIV-1).     

Targeted Synthesis of 3,3′-, 3,4′- and 3,6′-Phenylpropanoid Sucrose Esters

In this study, we report on an orthogonal strategy for the precise synthesis of 3,3′-, 3,4′-, and 3,6′-phenylpropanoid sucrose esters (PSEs). The strategy relies on carefully selected protecting groups and deprotecting agents, taking into consideration the reactivity of the four free hydroxyl groups of the key starting material: di-isopropylidene sucrose 2. The synthetic strategy is general, and potentially applies to the preparation of many natural and unnatural PSEs, especially those substituted at 3-, 3′-, 4′- and 6′-positions of PSEs.     

Nucleotides. Part XXXV. Synthesis of 3′-deoxyadenylyl-(2′–5′)-3′-deoxyadenyIyl-(2′–ω)-9-(ω-hydroxyalkyl)adenines

Via the phosphotriester approach, new structural analogs of (2′–5′)oligoadenyiates, namely 3′-deoxyadenylyl-(2′–5′)-3′-dcoxyadenylyl-(2′–ω)-9-(ω-hydroxyalkyl)adenines 18 – 21 , have been synthesized (see Scheme) which should preserve biological activity and show higher stability towards phosphodiesterases. The newly synthesized oligonucleotides 18 – 21 have been characterized by ¹H-NMR spectra, TLC, and HPLC analysis.     

Synthesis of 2,4′-dioxospiro[indoline-3,2′-thiazolidine]-5′-acetic acids: X-ray structure of 1-benzyl-3′-(4-chlorophenyl)-2,4′-dioxospiro- [indoline-3,2′-thiazolidine]-5′-acetic acid

The title compounds have been prepared by the cyclocondensation of mercaptosuccinic acid with isatin-3-imines. The 1-benzyl derivatives have been synthesized by simultaneously reacting 1-benzylisatin, substituted anilines and mercaptosuccinic acid. The structure of the products has been confirmed by X-ray diffraction measurements.     

Aminophosphordichloridite: A new phosphorylating reagent for one-pot synthesis of 3'-5'- or 2'-5'-linked diribonucleotide having defined sequence

3'-5'- or 2'-5'-linked diribonucleotides having definite sequences have been synthesized by an one-flask procedure utilizing the cyclic phosphorylation of the cis-glycol in the ribonucleosides with aminophosphordichloridites.     

Synthesis of α-2′-deoxynucleosides

α-Thymidine (4) was synthesized from thymidine (1) in 3 steps in 36% overall yield without using chro-matography and with the possibility of increasing the yield to 85% by reusing the remaining α,β-mixture. 1-(2-Deoxy-3,5-di-O-p-toluoyl-α-D-erythro-pentofuranosyl)thymine (3) was further converted to 1-(2-deoxy-α-D-erythro-pentofuranosyl)-5-methylcytosine (5) .     

Preparation of 3-(3′-,4′-Hydroxyphenyl)sydnones

3-(3′-,4′-Hydroxyphenyl)sydnones were prepared by dealkylation of 3-(3′-,4′-alkoxyphenyl)sydnones with concentrated sulfuric acid at room temperature in a range of 59 to 86% yield.     

γ- And δ-lycorane

Hydrogenation of -anhydrodihydrocaranine (V) or anhydrocaranine (VII) with Adams catalyst in acetic acid or the Hauptmann reduction of -dihydrocaranone (XX) yielded (—)γ-lycorane (XVII). Catalytic reduction of β-anhydrodihydrocaranine (IX) with palladium-carbon in ethanol gave (+)γ-lycorane (XVIII), while with Adams catalyst in acetic acid it afforded (+)δ-lycorane (XIX) along with (—)β-lycorane (III). Reduction of anhydrocaranine in ethanol gave (±)γ-lycorane which was also obtained by hydrogenation of anhydrolycorine (X). Based on these findings, the configurational structures of -, β-, γ- and δ-lycorane were established and the configuration of dihydrolycorine was confirmed.     

Isothermal degradation of poly-2,2′-(m-phenylene)-5,5′-bibenzimidazole

The isothermal degradation of poly-2,2′-(m-phenylene)-5,5′-bibenzimidazole in vacuo has been studied. Measurement of the increase in pressure with time, coupled with infrared analysis, was used to determine the distribution of the degradation products. Processes A and B with different second-order rate laws were determined to be significant in the temperature range of 550–700°C. Process A leads to the formation of equimolar quantities of hydrogen and ammonia and has an activation energy of 68 kcal/mole. Process B leads to the production of HCN, NH₃, and H₂ in the ratio of 1:1:2.5 and has an activation energy of 77 kcal/mole. The activation energies and the rate laws are consistent with a mechanism in which the initial degradation step is the bimolecular reaction of two aromatic rings.     

Some reactions of 4-[(2′,3′-diphenyl-6′-methoxy-5′-benzofuranyl)-methylene]- and 4-[(2′,3′-diphenyl-5′-methoxy-6′-benzofuranyl)-methylene]-2-phenyloxazolin-5-one

2,3-Diphenyl-5-formyl-6-methoxybenzofuran was reacted with hippuric acid to give 4-[(2′,3′-diphenyl-6′-methoxy-5′-benzofuranyl)methylene]-2-phenyloxazolin-5-one. The above mentioned oxazolone yielded 2,3-diphenyl-6-methoxybenzofuranylacetic acid by reaction with hydrazine hydrate, nitrous acid, benzene followed by acid hydrolysis. The reactions of the oxazolone with hydroxylamine hydrochloride and primary or secondary amines were also investigated.     

Synthesis of spiro[2H-indole-2,1′-1H-isoindole]-3,3′-diones,spiro[1H-isobenzofuran-1,2′-2H-indole]-3,3′-diones and spiro[benzofuran-2,1′-isobenzofuran]-3,3′-diones via transannular reactions of eight membered ring intermediates

An auto oxidation-rearrangement product 4 was isolated from a high dilution reaction of ninhydrin with 3,4,5-trimethoxyaniline in water. A general synthesis of this compound and its derivatives 4–6 was devised by oxidation of tetrahydroindeno[1,2-b]indol-10-ones 1–3 with sodium periodate to give isoindolo[2,1-a]-indole-6,11-diones 4–6 in good yield. Compounds 4–6 can be easily transformed into spiro[1H-isobenzofuran-1,2′-2H-indole]-3,3′-diones 8–10 , spiro[2H-indole-2,1′-1H-isoindole]-3,3′-diones 11–13 and isoindole[1,2-a:2′,1′-b]pyrimidine-5,15-diones 15, 16 in high yields. Analogous reactions were performed on 3-amino-5a, 10a-dihydroxybenzo[b]indeno[2,1-d]furan-10-one ( 17 ) to give a dibenzoxocintrione 18 , spiro-[benzofuran-2,1′-isobenzofuran]-3,3′-dione 19 and an isoindol-1-one 20 .