C-Formylation of Some 2(3H)-Benzazolones and 2H-1,4-Benzoxazin-3(4H)-one

1997 ◽  
Vol 62 (3) ◽  
pp. 494-497 ◽  
Author(s):  
Ognyan I. Petrov ◽  
Veneta B. Kalcheva ◽  
Antonina Ts. Antonova
Keyword(s):  
Methyl Ether ◽  
Trifluoroacetic Acid ◽  
Reaction Conditions

The C-formylation of 1,3-dimethyl-2(3H)-benzimidazolone and 4-methyl-2H-1,4-benzoxazin-3(4H)-one was performed using 1,1-dichloromethyl methyl ether at the Friedel-Crafts reaction conditions. The formylation of 3-methyl-2(3H)-benzoxa- and -thiazolone at the 6-position was carried out by modified Duff's method with hexamethylenetetramine in trifluoroacetic acid.

Optimum Conditions for Formation of Aflatoxin Mj-Trifiuoroacetic Acid Derivative

1987 ◽  
Vol 70 (6) ◽  
pp. 1047-1049 ◽  
Author(s):  
Robert D Stubblefield
Keyword(s):  
Trifluoroacetic Acid ◽  
Aflatoxin M1 ◽  
Optimum Conditions ◽  
Reaction Conditions ◽  
Reverse Phase ◽  
Glass Vial ◽  
Nonpolar Solvents ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Solvent Volume

Abstract Because thin-layer chromatographic (TLC) confirmation of identity and reverse-phase liquid chromatographic (LC) determination with fluorescence detection of aflatoxin M1 both require the derivative formed in the reaction of M1 and trifluoroacetic acid (TFA), various reaction conditions were studied to obtain complete derivative formation. Of the various organic solvents tested, the reaction between M1 and TFA proceeded best in the nonpolar solvents hexane and isooctane. Other parameters investigated were reaction temperature and time, aflatoxin M1 concentration, and solvent volume. The following procedure is considered optimum: 200 μL each of hexane and trifluoroacetic acid are mixed with M1 standard in a silylated glass vial or with milk residue in a regular glass vial with a Teflon-lined screw cap and heated 10 min at 40°C. The mixture is evaporated to dryness under N2, and the derivative is saved for TLC or LC. No unreacted aflatoxin M1 was detected by reverse-phase LC after this procedure was incorporated for analysis of milk samples.

Cyclization of cysteinylglycine sulfoxides under Pummerer reaction conditions

1979 ◽  
Vol 57 (18) ◽  
pp. 2412-2425 ◽  
Author(s):  
Saul Wolfe ◽  
Peter Michael Kazmaier ◽  
Hillar Auksi
Keyword(s):  
Acetic Anhydride ◽  
Trifluoroacetic Acid ◽  
Carboxyl Group ◽  
Reaction Conditions ◽  
Pummerer Reaction ◽  
Peptide Cyclization

A number of sulfoxides derived from 3-benzylthiopropionic acid, S-benzylcysteine, and S-phenylcystelne have been synthesized and exposed to typical Pummerer reaction conditions. Cyclization of the S-benzyl sulfoxides to six-membered or seven-membered heterocyclic rings (1,3-thiazin-4-ones and 1,3,6-oxathiazepines) is observed only in acetic anhydride solvent and only after conversion of the carboxyl group to an amide or peptide. Cyclization of S-phenylcysteinyl amides to β-lactams could not be achieved. The thiazolidine isomers of the six- and seven-membered rings have been synthesized and found not to be intermediates in the acetic anhydride reactions. The thiazolidines do rearrange to the six- and (or) seven-membered rings in anhydrous trifluoroacetic acid solvent. S-Benzylphthalimidocysteinylglycine sulfoxide, a 3:2 mixture of epimers at sulfur, affords a 3:2 mixture of isomeric thiazinones. A mechanism for these cyclizations is proposed, and it is suggested that the configuration at sulfur controls the configuration at the new asymmetric centre in the product.

Catalyst-free Synthesis of Aminomethylphenol Derivatives in Cyclopentyl Methyl Ether via Petasis Borono-Mannich Reaction

2020 ◽  
Vol 17 ◽  
Author(s):  
Jia-Qi Di ◽  
Hao-Jie Wang ◽  
Zhen-Shui Cui ◽  
Jin-Yong Hu ◽  
Zhan-Hui Zhang
Keyword(s):  
Secondary Amine ◽  
Methyl Ether ◽  
Mannich Reaction ◽  
Phenylboronic Acid ◽  
Functional Materials ◽  
Practical Method ◽  
Model Reaction ◽  
Arylboronic Acid ◽  
Reaction Conditions ◽  
Catalyst Free

Objective: Aminomethylphenol molecules have wider applications in pharmaceuticals, agrochemicals, plant protection and promising functional materials. The development of an efficient and practical method to prepare this class of compound is highly desirable from both environmental and economical points of views. Materials and Methods: In order to establish an effective synthetic method for preparing aminomethylphenol derivatives, the Petasis borono-Mannich reaction of salicylaldehyde, phenylboronic acid and 1,2,3,4-tetrahydroisoquinoline was selected as a model reaction. A variety of reaction conditions are investigated including solvent and temperature. The generality and limitation of the established method were also evaluated. Results and Discussion: It was found that model reaction can be carried out in cyclopentyl methyl ether at 80 oC under catalyst-free condition. This protocol with a broad substrate applicability, the reaction of various arylboronic acid, secondary amine and salicylaldehyde proceeded smoothly under optimal reaction conditions to afforded various aminomethylphenol derivatives in high yields. A practical, scalable, and high-yielding synthesis of aminomethylphenol derivatives was successfully accomplished. Conclusion: A catalyst-free practical method for the synthesis of minomethylphenol derivatives based on Petasis borono– Mannich (PBM) reaction of various arylboronic acid, secondary amine and salicylaldehyde in cyclopentyl methyl ether has been developed. The salient features of this protocol are avoidance of any additive/catalyst and toxic organic solvents, use cyclopentyl methyl ether as the reaction medium, clean reaction profiles, easy operation, and high to excellent yield.

Medium-sized cyclophanes. Part 62:1 Formylation of anti-[n.2]metacyclophanes — Through-space electronic interactions between two benzene rings

2003 ◽  
Vol 81 (3) ◽  
pp. 244-252 ◽  
Author(s):  
Takehiko Yamato ◽  
Tsuyoshi Furukawa ◽  
Kan Tanaka ◽  
Tsutomu Ishi-i ◽  
Masashi Tashiro
Keyword(s):  
Methyl Ether ◽  
Electrophilic Aromatic Substitution ◽  
Similar Reaction ◽  
Reaction Conditions ◽  
Ring Inversion ◽  
Electronic Interactions ◽  
Strained Molecules ◽  
Tert Butyl ◽  
Butyl Group ◽  
Tert Butyl Group

Formylation of anti-[n.2]metacyclophanes (1) (n = 2, 3, 4) with dichloromethyl methyl ether in the presence of TiCl4 occurred selectively at para-position to the internal methyl substituents of anti-[n.2]metacyclophanes. Similar reaction of anti-5,13-di-tert-butyl-8,16-dimethyl[2.2]metacyclophane (6a) with dichloromethyl methyl ether in the presence of TiCl4 led to ipso-formylation at the tert-butyl group to give anti-5-tert-butyl-13-formyl-8,16-dimethyl[2.2]-meta cyclophane (7a) as well as the corresponding 2,7-di-tert-butyl-trans-10b,10c-dimethyl-10b,10c-dihydropyrene (10), anti-5-tert-butyl-8,16-dimethyl-13-(3-methyl-1-butene-2-yl)[2.2]metacyclophane (8), and anti-5,13-di-tert-butyl-exo-1-hydroxy-8,16-dimethyl[2.2]metacyclophane (9) depending on the reaction conditions. The higher yield of ipso-formylated product is obtained in the presence of AlCl3 MeNO2 in 80% yield along with anti-5-tert-butyl-8,16-dimethyl-13-(3-methyl-1-butene-2-yl)[2.2]metacyclophane (13). Thus, the yield of ipso-formylation at the tert-butyl group of 6a was strongly affected by the activity of the formylation catalyst. Interestingly, in the formylation of anti-6,14-di-tert-butyl-9,17-dimethyl[3.2]metacyclophane (6b) under the same reaction conditions, syn-6,14-di-tert-butyl-7-formyl-9,17-dimethyl[3.2]metacyclophane (14b) was obtained in 40% yield arising from the anti-syn-ring inversion of the formylation intermediate along with ipso-formylation product 7b in 42% yield. In the formylation of anti-[4.2] meta cyclophane (6c) only the mono-ipso-formylated product 7c was obtained in 92% yield. The formation of a two-fold ipso-formation product, i.e., anti-5,13-diformyl-8,16-dimethyl[2.2]metacyclophane (3a), was not observed under the reaction conditions used. The mechanism of the ipso-formation as well as the formation of the present novel reaction products 8 and 9 is also discussed. Key words: cyclophanes, strained molecules, electrophilic aromatic substitution, ipso-formylation, σ-complex intermediates, through-space electronic interactions.

scholarly journals Atypisches Verhalten von Thiophenderivaten gegeniiber Reduktions- bzw. Thionierungs-Versuchen

2003 ◽  
Vol 71 (2) ◽  
pp. 51-56 ◽  
Author(s):  
T. Erker ◽  
K. Trinkl
Keyword(s):  
Reaction Temperature ◽  
Trifluoroacetic Acid ◽  
Reaction Conditions ◽  
Acetyl Group

To prepare required thiolactarns. initial experiments were done with the lactarns 1 - 3 and Lawessol reagent. However in preliminary trials. treatment of the compounds failed to give the desired molecules. Modification of the reaction conditions. paticularly with regard to the solvent and the reaction temperature. did not permit the preparation of the corresponding thiolactams. The keto function in position 6 was thought to be responsible for this atypical behaviour. Therefore. as the following step. the acetyl group in compounds 1 - 3 should be reduced to the corresponding ethyl derivatives. This reaction did not give the needed bicycles. Reduction of compounds 4 - 6 with triethylsilanel trifluoroacetic acid brought up compounds 7 - 9.

Synthesis and Crystal Structure of 4-[5-(2-Bromophenyl)-1,3,4-Thiadiazol-2-Ylthio]-2-(trifluoromethyl)thieno[2,3-d]pyrimidine

2014 ◽  
Vol 887-888 ◽  
pp. 703-706
Author(s):  
Ping Yang ◽  
Hui Gao ◽  
Yao Nie ◽  
Zhen Zeng ◽  
Jin Shun Zhao ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Trifluoroacetic Acid ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
H Nmr ◽  
Planar Conformation ◽  
Step Procedure ◽  
Title Molecule

4-[5-(2-Bromophenyl)-1,3,4-thiadiazol-2-ylthio]-2-(trifluoromethyl)thieno[2,3-d]pyrimidine was synthesized by a facile three-step procedure, including the cyclization of 2-aminothiophene-3-carbonitrile with trifluoroacetic acid, chlorination and nucleophilic substitution reaction. This protocol offers such advantages as mild reaction conditions, simple purification and good yields. The structure of the product was characterized by 1H NMR, MS, elemental analysis and single-crystal X-ray diffraction. X-Ray diffraction analysis reveals that the title molecule essentially assumes a planar conformation except for the F atoms.

Synthesis of 5,10,15-Tris(4-nitrophenyl)-20-hydroxylphenylporphyrin and its Spectrum Study

2012 ◽  
Vol 549 ◽  
pp. 269-273
Author(s):  
Huan Bao Fa ◽  
Hui Qi ◽  
Wei Yin ◽  
Dan Qun Huo ◽  
Chang Jun Hou
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Fluorescence Intensity ◽  
Trifluoroacetic Acid ◽  
Fluorescence Spectra ◽  
Reaction Conditions ◽  
Ir Spectrometry ◽  
Absorption And Emission ◽  
Novel Method ◽  
Uv Visible

5,10,15-Tris(4-nitrophenyl)-20-hydroxylphenylporph-yrin was synthesized by a novel method which was for the nitration of the phenyl groups of 5-(4-hydroxylphenyl)-10,15,20- triphenylporphyin(MHTPP) using NaNO2 and trifluoroacetic acid(TFA) and characterized using mass spectrometry, NMR spectroscopy, UV-visible, IR spectrometry. The mild reaction conditions produced higher yields and minimum macrocyclic degradation. Its fluorescence spectra was studied compared with MHTPP and tetraphenylporphyrin(TPP). The results showed that the absorption and emission bands of the product experienced red shifts and the fluorescence intensity weakened compared with MHTPP and TPP.

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