Synthesis of [D-alanine, 4'-azido-3',5'-ditritio-L-phenylalanine, norvaline4[alpha-melanotropin as a 'photoaffinity probe' for hormone-receptor interactions (author's transl)]

Synthesis of [D -alanine¹, 4′-azido-3′, 5′-ditritio-L -phenylalanine², norvaline⁴]α-melanotropin as a ‘photoaffinity probe’ for hormone-receptor interactions. The synthesis of an α-MSH derivative containing 4′-azido-3′,5′-ditritio-L -phenylalanine is described: Ac · D -Ala-Pap(³H₂)-Ser-Nva-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val · NH₂. This hormone analogue is being used for specific photoaffinity labelling of receptor molecules. The synthesis was performed in a way to minimize the number of radioactive steps and to introduce the radio-active and the photoaffinity label exclusively into position 2. The dipeptide N(α)-acetyl-D -alanyl- (4′-amino-3′,5′-diiodo)-L -phenylalanine was tritriated and transformed into the azido compound, N(α)-acetyl-D -alanyl-(4′-azido-3′,5′-ditritio)-L -phenylalanine which was then condensed with H · Ser-Nva-Glu(OtBu)-His-Phe-Arg-Trp-Gly-Lys(BOC)-Pro-Val · NH₂ to the tridecapeptide. The α-MSH analog displayed a specific activity of 11 Ci/mmol, and a biological activity of about 4 · 10⁹ U/mmol (10% of α-MSH).     

The synthesis of 2,2'-Dinor-carotenoids (author's transl)]

The Synthesis of 2,2′-Dinor-carotenoids. 2,2′-Dinor-carotenoids which include the naturally occurring actinioerythrol ( 1 ) and the blue carotenoid violerythrin ( 2 ) have been obtained by total synthesis. The synthesis starts with acetone and acetylene and yields compounds 1 and 2 as well as other carotenoids of the same type.     

The aromatic amino acid constituent of echinocandin B: 3, 4-dihydroxyhomotyrosine (author's transl)]

The aromatic amino acid constituent of Echinocandin B: 3,4-Dihydroxyhomotyrosine. The antifungal antibiotic echinocandin B gave upon treatment of its tetrahydroderivative with anhydrous trifluoroacetic acid and subsequent methanolysis the tripeptide threonyl-(4-hydroxyprolyl)-(4-oxohomotyrosine) methyl ester ( 8 ), which could be hydrolysed to 4-oxohomotyrosine ( 11 ). These facts together with the earlier described hydrolysis of the antibiotic to 1-amino-3-p-hydroxyphenyl-2-propanone ( 6 ) and the reductive hydrolysis to homotyrosine suggested the presence of 3,4-dihydroxyhomotyrosine ( 14 ) as a constituent amino acid of echinocandin B. This was confirmed by a degradation of the intact tetrahydro-polypeptide with perjodate yielding p-hydroxybenzaldehyde and by the isolation of free 3,4-dihydroxyhomotyrosine upon mild acidic treatment of the tetrahydro-polypeptide.     

On renal excretion of sodium 4-iodo-5-methylpyrazole-3-carboxylate-131I (author's transl)]

Sodium 4-iodo-5-methylpyrazole-3-carboxylate-131I(IMPC-131I) was synthesized by isotope exchange with Na 131I in the molten state to evaluate its potential usefulness as a renal function and/or imaging agent. Tissue distribution and clearance characteristics of IMPC-131I are described. Tissue distribution experiments in rats indicated a very high renal concentration of radioactivity following intravenous administration. At 5 min the kidney took up 27.8% of the injected dose (16.1% dose per gram) and the total activity in the kidney still accounted for 9.8% of the injected dose at 30 min, with only 1.2% localizing in the liver. The ratios for kidney-to-liver in the concentration of IMPC-131I were always higher than those of hippuran -131I throughout the period of the experiment. Within 24 hr, 78.6% of the injected dose were excreted in the urine. The autoradiographic and the scannographic studies were also performed. The present results suggest that IMPC-131I has potential as a new agent for both funciton and imaging studies of the kidney.     

Solid-state synthesis of poly(3',4'-dimethoxy-2,2':5',2"- terthiophene): comparison with poly(terthiophene) and poly(3',4'-ethylenedioxy-2,2':5',2"- terthiophene)

A new terthiophene monomer: 3',4'-dimethoxy-2,2':5',2"-terthiophene (TMT) was synthesized and characterized by 1H-NMR, 13C-NMR and FTIR. The solid-state oxidative polymerizations of TMT were performed in various ratios of oxidant (FeCl?) to monomer (TMT). The resulting polymers were characterized by 1H-NMR, FTIR, UV-vis-NIR, GPC, X-ray diffraction, CV, as well as TGA and conductivity measurements. The structure and properties of poly (TMT) were compared with those of polyterthiophene [poly(TT)] and poly (3',4'-ethylenedioxy-2,2':5',2"-terthiophene) [poly(TET)] prepared under the same polymerization conditions. After comparative analysis with poly(TT) and poly(TET), the effects of the dimethoxy substituent and FeCl? on the structural and physicochemical properties of the poly(TMT)s were discussed in depth. The comparison suggested that the dimethoxy-substituted polymer did not display higher crystallinity, thermal stability, conductivity and electrochemical activity than ethylenedioxy substituted one. The results also showed that the effect of FeCl? on poly(TMT) was similar that seen with the poly(TT), in which the oxidation degree, electrochemical activity and conductivity increased steadily with increasing [FeCl?/[TT] ratio. Furthermore, the poly(TMT) and poly(TT) are mostly made up of dimers with a small amount of higher molecular weight components.     

Total synthesis of 2',3',4',5',5' '-(2)h(5)-ribonucleosides: the key building blocks for NMR structure elucidation of large RNA

The diastereospecific chemical syntheses of uridine-2',3',4',5',5' '-(2)H(5) (21a), adenosine-2',3',4',5',5' '-(2)H(5) (21b), cytidine-2',3',4',5',5' '-(2)H(5)(2)H(5) (21c), and guanosine-2',3',4',5',5' '-(2)H(5) (21d) (>97 atom % (2)H at C2', C3', C4', and C5'/C5' ') have been achieved for their use in the solution NMR structure determination of oligo-RNA by the Uppsala "NMR-window" concept (refs 4a-c, 5a, 6), in which a small (1)H segment is NMR-visible, while the rest is made NMR-invisible by incorporation of the deuterated blocks 21a-d. The deuterated ribonucleosides 21a-d have been prepared by the condensation of appropriately protected aglycone with 1-O-acetyl-2,3,5-tri-O-(4-toluoyl)-alpha/beta-D-ribofuranose-2,3,4,5,5'-(2)H(5) (19), which has been obtained via diastereospecific deuterium incorporation at the C2 center of appropriate D-ribose-(2)H(4) derivatives either through an oxidation-reduction-inversion sequence or a one-step deuterium-proton exchange in high overall yield (44% and 24%, respectively).     

A general method for synthesis of folic acid, its conjugates and analogues (author's transl)]

A general method for synthesis of folic acid, its conjugates and analogues . A new and general method for the synthesis of folic acid, folic acid conjugates and folic acid analogues is described. The key step, i.e. the condensation of N(2′)-acetyl-6-formyl-pterine (I: R¹ ? COCH₃) with aminoaryl derivatives II, is achieved by refluxing in absolute ethanol to afford the azomethines III. NaBH₄-reduction followed by basic hydrolysis gives pure V products in high yield, free from 7-isomers.     

Synthesis of alkyl-5H-cyclopenta[b]pyrazines (author's transl)]

Synthesis of alkyl-5H-cyclopenta[b]pyrazines. Alkyl-5H-cyclopenta[b]-pyrazines (sometimes together with 5-alkylidene-5H-6,7-dihydrocyclopenta[b]pyrazines) are prepared by thermal degradation of 5-acetoxy-5H-6,7-dihydrocyclopenta[b]pyrazines; these are obtained by treatment of alkyl-5H-6,7-dihydrocyclopenta[b]pyrazine N-oxides with acetic anhydride. Cyclopenta[b]pyrazines which are potentially present in roasted food flavors possess interesting organoleptic properties.     

Synthesis of a homologous 3beta-hydroxycard-5,22-dienolide (author's transl)]

Synthesis of a homologous 3β-hydroxycard-5,22-dienolide. We describe the synthesis of 4′-[(3β-hydroxy-androst-5-en-17β-yl)methyl]-2′(5′)-furanone ( 22 ) starting from 3β-acetoxy-androst-5-ene-17β-carboxylic acid ( 5 ).     

A synthesis of vitamin A according to the sulfone method (author's transl)]

A Synthesis of Vitamin A According to the Sulfone Method. Starting from β-ionyl phenyl sulfone 7 and an appropriate allylic chloride 10 retinol 14 has been prepared by a direct procedure. Subsequent acetylation and isomerization led to crystalline all-E-vitamin A acetate 16 .     

The synthesis and photoactivated cytotoxicity of novel 5-phenyl-3- （2,2＇：5＇,2″-terthien-5-yl）-4,5-dihydro-lH-pyrazolines

A series of novel 5-phenyl-3-（2,2＇：5＇,2″-terthien-5-yl）-4,5-dihydro-lH-pyrazolines were synthesized in this report. Their photoactivated cytotoxicities on the 5podoptera litura （SL） cell line were evaluated using the MTT method. It was noticed that the inhibitory activities of all the conjugates was enhanced when irradiated with UV-A light. Compounds 4, 6 and 8 were found to be most effective with inhibition rates of 88.1%, 88.0%, and 90,5%, respectively, For compound B, the inhibition rate value was only slightly enhanced under the irradiation treatment （78.3%） compared to the dark treatment （74.8%）. The relationship analysis between structure and activity showed that the middle thiophene ring played an important role on the inhibitory activities. It was shown that these compounds could be the potential candidates for new photoactivated pesticides.