Indirect Iodination of Estrogenes via Triazenes

1993 ◽  
Vol 58 (11) ◽  
pp. 2729-2736 ◽  
Author(s):  
Jiří Protiva ◽  
Václav Křeček ◽  
Luděk Vlk ◽  
Hana Malinová ◽  
Eva Klinotová ◽  
...  
Keyword(s):  
Acid Medium ◽  
Mass Spectra ◽  
Sodium Iodide ◽  
Derivatives Of ◽  
C Nmr

Triazene derivatives of estrone and estradiol in position 2 and 4 were prepared. Their reaction with sodium iodide in an acid medium afforded the corresponding iodo derivatives. The 1H, 13C NMR and mass spectra of the compound prepared are discussed.

4-N-Benzazolylamino Derivatives of 3-Y-3-Buten-2-one

1992 ◽  
Vol 57 (3) ◽  
pp. 531-539 ◽  
Author(s):  
Viktor Milata ◽  
Dušan Ilavský ◽  
Igor Goljer ◽  
Ján Leško
Keyword(s):  
Nucleophilic Substitution ◽  
Mass Spectra ◽  
Spectral Measurements ◽  
Mild Conditions ◽  
Derivatives Of ◽  
C Nmr

Ethoxymethylene derivatives of 2,4-pentanedione (Ia), 3-oxobutanenitrile (Ib), methyl (Ic) or ethyl (Id) 3-oxobutanoate give with 4- or 5-aminobenzimidazole or benzotriazole, respectively, under mild conditions products of nucleophilic substitution II-V. Structure of these compounds was discussed on the basis of their spectral measurements - IR, UV, 1H, 13C NMR and mass spectra.

Photolysereaktionen mit Komplexen des Typs CpFe(CO)2R (R = Me, Et, Ph)+ / Photolytic Reactions with Complexes of the Type CpFe(CO)2R (R = Me, Et, Ph)+

1979 ◽  
Vol 34 (8) ◽  
pp. 1070-1077 ◽  
Author(s):  
H. G. Alt ◽  
M. Herberhold ◽  
B. H. Edwards
Keyword(s):  
Mass Spectra ◽  
Hydrogen Abstraction ◽  
Carbonyl Groups ◽  
Subsequent Reaction ◽  
Methyl Group ◽  
Hydrocarbon Solvents ◽  
Photoinduced Reaction ◽  
Intramolecular Hydrogen ◽  
Derivatives Of ◽  
C Nmr

Photolysis of CpFe(CO)2R complexes [R = Me (1a), Et (1b), Ph (1c)] in hydrocarbon solvents results in loss of the group R and formation of the binuclear compound [CpFe(CO)2]2 (2). In the case of 1a, the photogenerated methyl group reacts to give methane by intramolecular hydrogen abstraction from the Cp ring, or by intermolecular hydrogen abstraction either from the solvent or another methyl group. The photoinduced dealkylation of the ethyl compound 1b is explained by β-elimination (to give ethylene) and subsequent reaction of the hydrido intermediates thus formed with unchanged 1b (to give ethane). The photolysis of 1c leads to phenyl groups which abstract hydrogen from the solvent to give benzene; a noticeable amount of diphenyl is also observed if benzene is used as a solvent.In the presence of potential two-electron ligands L [L = PMe3, P(OMe)3], only the carbonyl groups of CpFe(CO)2Me (1a) are photolabile, and substituted derivatives of the type CpFe(CO)(L)Me [L = PMe3 (3a), P(OMe)3 (4a)] and CpFe(L)2Me [L = P(OMe)3 (5a)] are formed.The photoinduced reaction of CpFe(CO)2Me (1a) and diphenylacetylene in solution gives metallocyclic derivatives containing either one or two diphenylacetylene units. On the basis of the IR, the 1H and 13C NMR, and the mass spectra, the complex CpFe(CO)(Ph2C2-COMe) (6a) is assigned a structure containing a vinyl-ketone unit in a five-membered metallocycle, while in CpFe(Ph4C4-COMe) (7a) a tetraphenylbutadienyl group appears to be incorporated into a seven-membered metallocycle

Synthesis and characterization of chlorophyll a enol derivatives: Chlorophyll a tert-butyldimethylsilyl-enol ether and 131-deoxo-131, 132-didehydro-chlorophyll a

2016 ◽  
Vol 20 (05) ◽  
pp. 590-601
Author(s):  
Paavo H. Hynninen ◽  
Markku Mesilaakso
Keyword(s):  
Chlorophyll A ◽  
Mass Spectra ◽  
Electronic Absorption Spectra ◽  
Enol Ether ◽  
Sterically Hindered ◽  
Work Up ◽  
Derivatives Of ◽  
C Nmr

Using the sterically hindered base, 1,8-diazabicyclo[5.4.0]undec-7-ene, for enolization and tert-butyldimethylsilyl-trifluoromethanesulfonate for silylation, chlorophyll (Chl) [Formula: see text] produced after 15 min at 0 [Formula: see text]C in deaerated pyridine solution under argon, after work-up and chromatographic purification on a sucrose column, tert-butyldimethylsilyl-enol ether of Chl [Formula: see text] in a yield of 77%. The 131-deoxo-131,132-didehydro-chlorophyll [Formula: see text], was obtained in a yield of 23% through a reaction sequence, where Chl [Formula: see text] was first reduced with sodium borohydride to 13[Formula: see text]-hydroxy-Chl [Formula: see text], which via demetalation yielded 13[Formula: see text]-hydroxypheophytin [Formula: see text]. In the presence of the sterically hindered base, 1,8-bis(dimethylamino)naphthalene, trifluoroacetylimidazole dehydrated 13[Formula: see text]-hydroxypheophytin [Formula: see text] to 131-deoxo-131,132-didehydro-pheophytin [Formula: see text], which after metalation yielded 131-deoxo-131,132-didehydro-Chl [Formula: see text]. Using 1,8-bis(dimethylamino)naphthalene and trifluoroacetylimidazole, the straight conversion of 13[Formula: see text]-hydroxy-Chl [Formula: see text] to 131-deoxo-131,132-didehydro-Chl [Formula: see text] was found unsuccessful. The major products were characterized by electronic absorption spectra (UV-vis) and practically completely assigned 1H and [Formula: see text]C NMR spectra. Some intermediates of the syntheses were also characterized by ESI-TOF mass spectra. Compared with Chl [Formula: see text], the macrocyclic ring-current in the synthesized Chl [Formula: see text] enol derivatives was found weakened by the expansion of the [Formula: see text]-system to include the isocyclic ring E. Nevertheless, these enol derivatives were still considered to be diamagnetic and aromatic. The possibility of the functional role of the enol derivatives of chlorophyll in photosynthesis is discussed.

Inductive effect in EI-mass spectra of some 5,6-dihalogenides and 5,6-halohydrins of 5α-cholestan-3β-ol and 3β-acetoxy-5α-cholestane

1982 ◽  
Vol 47 (11) ◽  
pp. 2946-2960 ◽  
Author(s):  
Antonín Trka ◽  
Alexander Kasal
Keyword(s):  
Mass Spectra ◽  
Inductive Effect ◽  
Molecular Ions ◽  
Hydroxyl Group ◽  
Halogen Atoms ◽  
Derivatives Of

Partial EI-mass spectra of 3β-hydroxy- and 3β-acetoxy-5α-cholestanes substituted in positions 5α-, 6β- or 5α,6β- with a hydroxyl group or halogen atoms (fluorine, chlorine, bromine) are presented. The molecular ions of 5α,6β-disubstituted derivatives of 3β-hydroxy-5α-cholestane (or of its 3-acetate) are considerably more stable than the corresponding monosubstituted derivatives if at least one of the pair of the vicinal substituents is chlorine or fluorine. This increase in stability, most striking in 5α- and 6β-fluoro compounds, is explained by the inductive effect.

Thermal cyclocondensations of 3-N(4- and 5-benzimidazolyl and benztriazolyl)amino derivatives of 2-propenoic acid

1987 ◽  
Vol 52 (12) ◽  
pp. 2918-2925 ◽  
Author(s):  
Viktor Milata ◽  
Dušan Ilavský
Keyword(s):  
Uv Spectra ◽  
Propenoic Acid ◽  
Amino Derivatives ◽  
Derivatives Of ◽  
C Nmr ◽  
Ir And Uv Spectra

The cyclization of 3-N(4- and 5-benzimidazolyl and benztriazolyl)amino-2-cyano- and 2-ethoxycarbonyl-2-propenoate esters Ia, b-IVa, b under the conditions of the Gould-Jacobs reaction leads to angularly ring-fused substituted imidazo or triazolo[4,5-f] (V, VI) and [4,5-h] (VII, VIII) quinolines, respectively. The esters Vb-VIIIb have been transformed into the corresponding chloroderivatives Vc-VIIIc. 3-N(5-Benzimidazolyl and 5-benztriazolyl)amino-2-cyano-2-propenenitriles are cyclized in the presence of aluminium(III) chloride to give the aminoquinolines Vd, VId. The structure of the products has been characterized by their 1H, 13C NMR, IR, and UV spectra.

Synthesis of 2-amino-5,7-dimethyl-4-oxopyrido[3,4-e]-1,3-thiazines

1983 ◽  
Vol 48 (12) ◽  
pp. 3426-3432 ◽  
Author(s):  
Dušan Koščík ◽  
Pavol Kristian ◽  
Ondrej Forgáč
Keyword(s):  
Spectral Data ◽  
Chlorine Atom ◽  
Mass Spectra ◽  
High Reactivity ◽  
Secondary Amines ◽  
Dimroth Rearrangement ◽  
H Nmr ◽  
New Synthesis ◽  
C Nmr

New synthesis of pyrido[3,4-e]-1,3-thiazines consisting in reaction of 2,6-dimethyl-4-chloronicotinoyl isothiocyanate with primary or secondary amines, or with benzaldehyde phenylhydrazone, is described. High reactivity of the chlorine atom does not allow isolation of the corresponding thioureas, arising as intermediates, except in the case of the benzylamino derivative. Structure of the products was unequivocally confirmed by their spectral data (IR, UV, 1H NMR, 13C NMR and mass spectra). The synthesized derivatives do not undergo the Dimroth rearrangement.

Oxynemorensine, an alkaloid from Senecio nemorensis L., var. subdecurrens GRISEB

1980 ◽  
Vol 45 (2) ◽  
pp. 548-558 ◽  
Author(s):  
Antonín Klásek ◽  
Petr Sedmera ◽  
Jindřich Vokoun ◽  
Anna Boeva ◽  
Svatava Dvoráčková ◽  
...  
Keyword(s):  
Unsaturated Acid ◽  
Mass Spectra ◽  
H Nmr ◽  
C Nmr

From S. nemorensis L., var. subdecurrens GRISEB. there were isolated the previously obtained alkaloids nemorensine (I), retroisosenine (II), bulgarsenine (III) and, in addition, the alkaloid oxynemorensine which was assigned the structure VIII on the basis of the interpretation of the 1H-NMR, 13C-NMR, mass spectra, and on that of the identification of the products of hydrolysis and reduction. Furthermore, the isolation of the cis-nemorensic acid (V) as well as that of the unsaturated acid IV, and the transformation of bulgarsenine (III) to nemorensine (I) were described.

Preparation of 2,3-Dideoxy-2,3-epimino and 3,4-Dideoxy-3,4-epimino Derivatives of 1,6-Anhydro-β-D-hexopyranoses by Mitsunobu Reaction

1998 ◽  
Vol 63 (6) ◽  
pp. 813-825 ◽  
Author(s):  
Jiří Kroutil ◽  
Tomáš Trnka ◽  
Miloš Buděšínský ◽  
Miloslav Černý
Keyword(s):  
Nmr Spectra ◽  
Mitsunobu Reaction ◽  
Derivatives Of ◽  
C Nmr

A series of new 2-, 3- and 4-benzylamino-2-, 3- and 4-deoxy derivatives of 1,6-anhydro-β-D-hexopyranoses were prepared from 1,6:2,3- and 1,6:3,4-dianhydro-β-D-hexopyranoses by treatment with benzylamine and converted into 2,3-(N-benzylepimino)-2,3-dideoxy- and 3,4-(N-benzylepimino)-3,4-dideoxy-β-D-hexopyranoses of the D-allo, D-galacto and D-talo configuration by Mitsunobu reaction. The structures of benzylamino and benzylimino derivatives were confirmed by 1H and 13C NMR spectra.

Sign in / Sign up

Export Citation Format

Share Document