STUDIA UNIVERSITATIS BABE. Cluj- Napoca, Romania, Phone CUPRINS CONTENT SOMMAIRE INHALT CRISTINA MORAR, LAVINIA COST, MIRCEA DARABANTU, Concise Synthesis of Some (4- Aminophenoxy)Alkanoic Acids Based on Paracetamol.. RAUL RANETE, PETRONELA M. ANDREEA IULIANA GULIE (KUI), M. A Chemometric Approach SONIA SUVAR, ELENA HORJ, PAULA PODEA, ANDREEA IORDACHE, DANIEL COCAN, MONICA CULEA, Fatty Acids Determination in Trout Plasma and Meat by GC- MS ANDREEA DR. Study Case: The Northern Part of Sibiu County ANCU? Indirect pulp capping: a survey. This study addresses the acceptance of the clinical practice of indirect pulp capping. These bacteria use ingredients found in our diet and saliva to grow. A TheraCal LC liner was placed on both teeth. The photos show after all the caries were. Title: Dental News Sept 2013, Author. 4,7,8,13,14,15,16 A soft diet is followed for. MICHAELA BIANCA SOPORAN, OVIDIU NEME. Science Citation Index Expanded (also known as Sci. Search ) Chemistry Citation Index Journal Citation Reports/Science Edition. STUDIA UBB CHEMIA, LX, 2, Tom I, 2. RECOMMENDED CITATION) CONCISE SYNTHESIS OF SOME (4- AMINOPHENOXY)ALKANOIC ACIDS BASED ON PARACETAMOL CRISTINA MORAR a, LAVINIA COST a, MIRCEA DARABANTU a,* ABSTRACT. Starting from N- (4- hydroxyphenyl)acetamide (Paracetamol), a three steps synthesis of (4- aminophenoxy)acetic acid and 4- (4- aminophenoxy) butyric acid is comparatively discussed. Keywords: (4- aminophenoxy)acetic acid, 4- (4- aminophenoxy)butyric acid, Williamson etherification, acidolysis INTRODUCTION (4- Aminophenoxy)acetic acid 1a and 4- (4- aminophenoxy)butyric acid 1b (Scheme 1) are known compounds as early as for the end of XIXcentury and the starting of XX- century . O O ( ) n OH 1a (n=1), 1b (n=3) H 2 N Scheme 1 The first reported synthesis of (4- aminophenoxy)acetic acid consisted of reduction of its corresponding nitro precursor, the last one being available from Williamson etherification of 4- nitrophenol with monochloroacetic acid in alkaline conditions . Closer to our days, the same etherification strategy still was actual by using, in the key step, N- (4- hydroxyphenyl)acetamide (Paracetamol) in reaction with monochloroacetic acid . However, the expected soft nucleophilicity of the conjugated p- substituted phenoxides 1 prompted other authors to explore the use of a Babe. ![]() DARABANTU bromoacetic acid . Overall, the nowadays increased interest in (N,O- masked) forms of (4- aminophenoxy)acetic acid arises from their bioimpact, i.
Sample records for pulp capping materials. Calcicur (Voco), Calcimol LC (Voco), TheraCal LC (Bisco), MTA Angelus (Angelus), Biodentine (Septodont). Probiotic yoghurt in previous studies and probiotic yoghurts enriched various ingredients such as guava pulp, legumes, oat bran etc. In contrast, there are very few reports concerning the synthesis of 4- (4- aminophenoxy)butyric acid 1b (Scheme 1) in spite of its first mentioning in the literature in 1. Similar to its lower homologue 1a, 1b can be obtained by reduction of 4- (4- nitrophenoxy)butyric acid resulted, from the regioselective ring cleavage of - butyrolactone upon treatment with sodium 4- nitrophenoxide (Scheme 2) . Therefore, the aim of the present preliminary communication is to present a common and concise synthetic pathway towards (4- aminophenoxy)alkanoic acids 1a and 1b (Scheme 1) based on a Williamson approach. RESULTS AND DISCUSSION The chemistry we performed is resumed in Scheme 3. They consisted of Williamson etherification of Paracetamol (I, 9. In step III, we isolated the free amine 1a by manipulating its solubility in water in such a way that we avoided contamination with potassium chloride. CONCISE SYNTHESIS OF SOME (4- AMINOPHENOXY)ALKANOIC ACIDS BASED ON PARACETAMOL In order to access 4- (4- aminophenoxy)butyric acid 1b, we first planned the ring opening of - butyrolactone with the use of sodium phenoxide of Paracetamol in similar conditions with those already reported in the case of sodium 4- nitrophenoxide (Scheme 2) . ![]() In our hands no reaction occurred, the starting N- (4- hydroxyphenyl)acetamide being recovered. That is, once more we moved our interest towards Williamson I Br- (CH 2 ) n - CO- OEt Ac- HN OH K 2 CO 3 Ac- HN O- (CH 2 ) n - CO- OEt n=1 Paracetamol - Cl + H 3 N O- CH 2 - COOH 3a (9. III 0. 5 equiv. HCl O- (CH 2 ) n - COOH - Cl + H 3 N O- (CH 2 ) 3 - COOH 1a (n=1) 8. Ac- HN 3b (7. 1%) 3c O- (CH 2 ) 3 - COOH Acidolysis of compound 2b Time (h) Molar composition (%) b b c d Key - Cl + H 3 N OH 3d I (n=1) 2a: 3. III (n=1, 3) 1a, 1b: 0. K 2 CO 3 / H 2 O / r. Scheme 3 methodology. Thus, inspired from the similar reactivity of N- (4- hydroxybenzyl)acetamide . However, acidolysis (II) of 2b carried out in identical conditions as for 2a, resulted in a crude reaction mixture whose 1 H NMR spectrum revealed, besides formation of the desired 3b, the existence of the hydrochloride of 4- aminophenol 3d issued from the acidolysis of the etheric connection (Figure 1). H NMR monitoring of the process showed the reaction reaching completion within 2 h, i. As for 1a, the free amine 1b was isolate simply (III) by modulating its solubility in water against that of potassium chloride. To conclude, the overall yield in the synthesis of 1b was 3. Compound 2b was previously mentioned by Katsura and co- workers in 2. Ref. DARABANTU CONCLUSIONS Starting from N- (4- hydroxyphenyl)acetamide, we described a three steps expeditious synthetic pathway in the direction of two (4- aminophenoxy)alkanoic acids. The common key step, a Williamson etherification yielding amidoesters of the target aminoacids, appears to be a good option if ethyl bromoalkanoates are used. In contrast, the key step, A - Cl + H 3 N O OH 3d COOH 3b - Cl + H 3 N B O COOH 3b - Cl + H 3 N C O COOH 3b - Cl + H 3 N O COOH 3c Me Ac- HN Figure 1. H NMR monitoring of acidolysis of amidoester 2b (6. MHz, D2. O, 2. 98 K): crude reaction mixture after 1. A), 2 h (B), 1 h (C). N,O- deprotection of the resulting amidoesters by acidolysis, strongly depends on the size of the (poly)methylenic chain (n=1 vs. CONCISE SYNTHESIS OF SOME (4- AMINOPHENOXY)ALKANOIC ACIDS BASED ON PARACETAMOL EXPERIMENTAL SECTION General. Melting points were measured on an Electrothermal instrument and are not corrected. NMR spectra were recorded on Bruker AV 4. AV 6. 00 instruments operating at 4. MHz for 1 H and at 1. MHz for 1. 3 C nuclei respectively. All chemical shifts (. TLC was performed by using aluminium sheets with silica gel 6. F 2. 54 (Merck ). IR spectra were recorded on a Bruker FT- IR Vector 2. Spectrometer. Microanalyses were performed on a Carlo Erba CHNOS 1. Mass spectra were carried out on a Schimadzu GC- MS QP- 2. PLUS instrument equipped with a Column HP- 5. MS under EI (7. 0 ev) ionisation. All solvents and reagents were of analytical grade and required no purification prior to use. Typical procedure for Williamson etherification. Preparation of compound 2b. Into a DMF (3. 0 ml) solution containing N- (4- hydroxyphenyl) acetamide (3. K 2 CO 3 (1. 0. 8. The resulted suspension was heated at 7. C for 1. 6 h then let to stir at room temperature for additional 7. Water (5. 0 ml) and ethyl acetate (1. The organic layer was washed with water to complete removal of DMF (5 5. Na 2 SO 4 and evaporated under reduced pressure. The crude solid product was crystallised from min. Ethyl (4- N- acetylamino)phenoxyacetate (2a); yield 9. C 1. 2 H 1. 5 NO 4 (2. C, 6. 0. 7. 5; H, 6. N, 5. 9. 0 %. 1. 3 C NMR in J mod (1. MHz, DMSO- d 6, 2. K) . GC- MS (Me. OH) m/z (rel. DARABANTU Ethyl 4- (4- N- acetylamino)phenoxybutyrate (2b); yield 7. C 1. 4 H 1. 9 NO 4 (2. C, 6. 3. 3. 8; H, 7. N, 5. 2. 8%. 1. 3 C NMR in J mod (1. MHz, DMSO- d 6, 2. K) . GC- MS (Me. OH) m/z (rel. Typical procedure for acidolysis. Preparation of compound 3b. Ethyl 4- (4- N- acetylamino)phenoxybutyrate 2b (3. The resulted white suspension was cooled at 0 o C for 2. THF to afford 2. 4. C 8 H 1. 0 Cl. NO 3 (2. C, 4. 7. 1. 9; H, 4. N, 6. 8. 8%. 1. 3 C- RMN in J mod (1. MHz, D 2 O, 2. 98 K) . GC- MS (Me. OH) m/z (rel. Aminophenoxy)butyric acid hydrochloride (3b); yield 7. C (aq. C 1. 0 H 1. Cl. NO 3 (2. 31. 0. C, 5. 1. 8. 4; 1. CONCISE SYNTHESIS OF SOME (4- AMINOPHENOXY)ALKANOIC ACIDS BASED ON PARACETAMOL H, 6. N, 6. 0. 5%. 1. 3 C NMR in J mod (1. MHz, D 2 O, 2. 98 K) . GC- MS (Me. OH) m/z (rel. Typical procedure for isolation of (4- aminophenoxy)alkanoic acids as free amine. Isolation of compound 1b. To this solution, anhyd. K 2 CO 3 (0. 7. 3 g, 5. The resulted suspension was stirred for 1 h at r. C 8 H 9 NO 3 (1. 67. C, 5. 7. 4. 8; H, 5. N, 8. 3. 8%. 1. 3 C- RMN in J mod (1. MHz, DMSO- d 6, 2. K) . GC- MS (Me. OH) m/z (rel. Aminophenoxy)butyric acid (1b); yield 7. C (H 2 O) (Lit o C . C 1. 0 H 1. 3 NO 3 (1. C, 6. 1. 5. 3; H, 6. N, 7. 1. 8; %. DARABANTU 6. H, d, 3 J H,H =8. Hz, H- 2, - 6, Ar) ppm. C NMR in J mod (1. MHz, DMSO- d 6, 2. K) . GC- MS (Me. OH) m/z (rel. ACKNOWLEDGMENT The financial support from a Grant provided by the Research Council Romania (project PN- II- ID- PCE ) is gratefully acknowledged. Jain, Der Pharma Chem., 2. D. J. Chem., 1. 98. R. S. Bezwada, US Pat B2/ ; b) K. Chem., 2. 00. 8, 1. V. A. USSR (English Translation), 1. Zh. Khim., 1. 97. M. Pap Scientific and Technical Bulletin of Polytechnic Institute Traian Vuia Timisoara, Chemistry Series, 1. W. 2. 01. 5/4. 55. A1/ ; d) X. Lett., 2. STUDIA UBB CHEMIA, LX, 2, Tom I, 2. RECOMMENDED CITATION) SILICA GEL MODIFIED WITH FUNCTIONALIZED CALIXARENES. PREPARATION AND CHARACTERIZATION RAUL RANETE a, PETRONELA M. This work presents the synthesis and characterization of novel products obtained by the chemical bonding of lower rim substituted calix. The products were investigated by thermogravimetric analysis (DTG, EGA), surface area analysis (BET), as well as by electron microscopy (TEM, SEM). Keywords: functionalized silica gel, calixarenes, thermal analyses, electronic microscopy. The cavity formed by the phenolic rings and the possibility of functionalizing the calixarenic framework with various organic groups, make these organic macrocycles very interesting for a wide range of applications including biomedical research . In recent years, more emphasis was put on the immobilization of calixarenes on silica gel substrates, thus improving their possible application in separation sciences . One of the most accessible ways to bond calixarene macrocycles to the Si. O 2 layer is through alcoxysilanes of the type X- (CH 2 ) n - Si(OR ) 3 . Arany Janos, nr 1. RO b Institutul de Cercet. Cluj- Napoca RO * Corresponding author: 1. R. The reactions were performed in anhydrous conditions by the nucleophilic attack of hydroxyl groups from the silica gel surface at the APTMS spacer, with the elimination of methanol .
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