Download (8Mb) - Etheses - Saurashtra University

More documents

Recommendations

Info

Chapter-4 Copper Catalyzed Microwave Assisted One Pot Synthesis of 2-Aminoimidazole-Triazole Framework via Dimorth Rearrangement and Click Reaction. Br R 2 N N n N OH R 1 n = 1,2 N 3 ABSTRACT One-pot Microwave-Assisted Synthesis Cu(OAc) 2 (5 mol %) N 2H 4 (2 equiv) R 3 (1.2 equiv) MW, 100 o C, 2-5 min R 2 N NH N H 22 examples, upto 90% yield R 1 N N n N R3 A microwave assisted one-pot Cu(II)-catalyzed protocol was developed for the construction of 2-AI-T framework. This process combining two consecutive steps of dimorth rearrangement and click reaction represents a useful protocol for the smooth synthesis of novel 2-aminoimidazole-triazole derivatives. Publication [1] Copper Catalyzed Microwave Assisted One Pot Synthesis of 2- Aminoimidazole-Triazole Framework Org.lett (manuscript in preparation)
4.1 Introduction There are only a few approaches that describe the direct synthesis of 2aminoimidazoles and their biological activity 1-5 . The earliest method involves condensation of α-aminocarbonyl compounds with cyanamide or their synthetic equivalents 6,7 . This method is most commonly used for the direct construction of the 2-aminoimidazole ring. Other general applicable strategies are cyclocondensation of α-bromoketone with N-acetylguanidine in acetonitrile 8 , iminophosphorane-mediated cyclization of α –azido esters 9 , ammonolysis of 2-amino-1,3-oxazol-3-iumsalts 10 , sequential functionalization of 1,2-diprotected imidazole ring with different electrophiles 11 . Most of them involve long experimental procedures, the use of unstable precursors and tiresome workup process. Accordingly, the development of straightforward and general procedures for the synthesis of diversely substituted 2aminoimidazoles from readily available precursors is highly warranted. Herein, we report a rapid and highly efficient Cu-mediated synthesis of 2-aminoimidazoletriazole framework via click reaction and dimorth rearrangement. “Click chemistry” has emerged as a fast and efficient approach to synthesis of novel compounds with desired function making use of selected “near perfect” reactions. 12 (very fast, selective, high-yield, and wide scope). The Dimroth rearrangement 13 is an isomerization of heterocycles that consists in a translocation of endo- or exocyclic heteroatoms through a ring-opening-ring-closure sequence. It can be catalyzed by acids, bases, heat or light. Recently group of Erik 14 reported a new one pot microwave assisted synthesis of substituted 2-amino-1H- imidazoles from readily available 2-aminopyrimidine (1) and α-bromoketone (2). The first step was performed by heating N-(3azidopropyl)pyrimidin-2-amine (1) and 2-bromo-1-phenylethanone (2) at 75 o C for 3 h resulting in the formation of hydroxyl salt (3) which undergoes dimorth type rearrangement by 7 equiv of NH2NH2.H2O resulting in the formation of N-(2-azido)- 1H-imidazol-2-amine. Final step of click reaction was performed under microwaveirradiation using phenylacetylene (1.5.equiv), Cu(Oac)2 (10 mol %)as catalyst at 100 o C 10 min with a maximum power of 40W to obtain 2-AI-T scaffold (5). (Scheme 1)
Page 1 and 2:
Saurashtra University Re - Accredit
Page 3:
JANUARY-2011 Statement under O. Ph.
Page 7 and 8:
Acknowledgment This thesis arose in
Page 9 and 10:
since I was a child. My Mother Hans
Page 11 and 12:
CHAPTER - 2 Microwave Assisted Synt
Page 13 and 14:
5.5 Results and discussion 156 5.6
Page 15 and 16:
Ms Mesyl MW Microwave NBS N-bromosu
Page 17 and 18:
1. Microwave Assisted Organic Synth
Page 19 and 20:
1.4 Heating Mechanism In microwave
Page 21 and 22:
1.5. Effects of solvents Every solv
Page 23 and 24:
1.7 Application of microwave in org
Page 25 and 26:
aromatic amines, Lancini’s group
Page 27 and 28:
1.9 2-Aminoimidazole Alkaloids The
Page 29 and 30:
Recently group of Erik 83 described
Page 31 and 32:
1.10 Methods for the preparation of
Page 33 and 34:
R 1 O X R 2 NH 2 H 2N NAc R 1 HN R
Page 35 and 36:
this manifold, was reported in 1925
Page 37 and 38:
Another route to 4(5)-acyl-2-amino-
Page 39 and 40:
this series of compounds against th
Page 41 and 42:
documented. Extra care is needed be
Page 43 and 44:
Very recently the research group of
Page 45 and 46:
OH a,b O N H2N N Boc N 3 H N R N N
Page 47 and 48:
1.12.2 Biofilm Growth Cycle 1) Plan
Page 49 and 50:
can survive both the onslaught of a
Page 51 and 52:
[26] Leadbeater, N. E. (2004) Chemi
Page 53 and 54:
[86] Kreutzberger, A. (1962) J. Org
Page 55 and 56:
Microwave Assisted Synthesis & Stru
Page 57 and 58:
2.1 Introduction As described in ch
Page 59 and 60:
2.3 Proposed Mechanism: Regarding t
Page 61 and 62:
No. 12 60 120 traces 84 a All react
Page 63 and 64:
the development of biofilm related
Page 65 and 66:
In first instance, a series of 2-hy
Page 67 and 68:
Br N N N R 1 OH Br N N N R 1 OH Fig
Page 69 and 70:
do have a very strong effect agains
Page 71 and 72:
2.6 Conclusion In the present study
Page 73 and 74:
2.8 Biological assays 2.8.1 Static
Page 75 and 76:
2.9 Experimental protocol: 2.9.1 Ge
Page 77 and 78:
temperature of 80 °C and a maximum
Page 79 and 80:
29.5,29.4, 29.2, 27.0, 22.6, 14.1.
Page 81 and 82:
Yield: 78 %. 1 H NMR (300 MHz, CDCl
Page 83 and 84:
N Br N N C 14H 29 OH Yield: 72 %. 1
Page 85 and 86:
(75.5 MHz, CDCl3): δ = 167.7, 154.
Page 87 and 88:
N Br N N C 14H 29 OH Cl Yield: 90 %
Page 89 and 90: 2-(3,4-Dichlorophenyl)-2-hydroxy-1-
Page 91 and 92: N Br N N C 8H 17 OH NO 2 Yield: 49
Page 93 and 94: C3H7 HN N N H Cl Cl Yield : 70 %. 1
Page 95 and 96: (s, 1H), 3.16 (s, 3H), 1.80 (m, 2H)
Page 97 and 98: 5-(4’-Nitrobiphenyl-4-yl)-N-octyl
Page 99 and 100: 2.11 Representative NMR spectra 2.1
Page 101 and 102: 2.11.3 10.4329 0.7429 151.5720 10.0
Page 103 and 104: [21] Matz C, McDougald D, Moreno A.
Page 105 and 106: Chapter-3 Structure Activity Relati
Page 107 and 108: imidazoles, where the addition of a
Page 109 and 110: 3.4 Result and Discussion It was fo
Page 111 and 112: No. H 2N Compound Code N N C8H17 R1
Page 113 and 114: medium used in the set-up to monito
Page 115 and 116: H 2N N N N H2N N R R Figure-1 Effec
Page 117 and 118: 3.5.3 Cyclo-alkyl 2-aminoimidazoles
Page 119 and 120: 3.6. Conclusion In the present stud
Page 121 and 122: 3.8. Experimental protocols 3.8.1 G
Page 123 and 124: 122.6, 54.6, 33.3(×2), 27.3 (×2),
Page 125 and 126: Yield: 52 %. 1 H NMR (300 MHz, CDCl
Page 127 and 128: 5-(4-Chlorophenyl)-1-cyclooctyl-1H-
Page 129 and 130: Yield: 50 %. Mp: 76-78 ° C. 1 H NM
Page 131 and 132: 5-(4-Chlorophenyl)-1-cyclobutyl-1H-
Page 133 and 134: Yield: 66%. 1 H NMR (300 MHz, CDCl3
Page 135 and 136: 3.10 Representative NMR spectra 3.1
Page 137 and 138: 3.11 References [1] (a) Alvi K. A,
Page 139: Copper Catalyzed Microwave Assisted
Page 143 and 144: (Table-1, No- 6). Next reaction tem
Page 145 and 146: No. Product, Yield b (%) No. Produc
Page 147 and 148: 4.4 Possible Mechanism Regarding th
Page 149 and 150: 4.7 Experimental protocols 4.7.1 Ge
Page 151 and 152: Yield: 69 %. 1 H NMR (300 MHz, CDCl
Page 153 and 154: 1-(3-Azidopropyl)-2-(3,4-dichloroph
Page 155 and 156: Yield: 84 %. 1 H NMR (300 MHz, DMSO
Page 161 and 162: 1H), 1.66 (m, 6H), 1.70 (m, 2H). 13
Page 163 and 164: 5.48 Hz, 2H), 3.59 (m, 2H), 3.16 (d
Page 165 and 166: 4.10 References [1] For a general r
Page 167 and 168: Crystal and Molecular Structure Ana
Page 169 and 170: 5.1 Introduction The membrane efflu
Page 171 and 172: oscillation range of 5˚ and proces
Page 173 and 174: C12-C13 1.372(4) C32-C37 1.390(3) C
Page 175 and 176: Fig.-3: Packing of the molecules wh
Page 177 and 178: 1 H NMR (400 MHz CDCl3): δ = 7.57-
Page 179 and 180: 5.9.2 13 C spectra of bs-DP-7
Page 181 and 182: SUMMARY The work represented in the
Page 183 and 184: CONFERENCES/SEMINARS/WORKSHOPS ATTE
Page 185: PUBLICATIONS [1] One-Pot Microwave-
Page 200 and 201:
Scheme 2 Competitive formation of 1
Page 202 and 203:
Table 2 continued 9 10 11 12 N hydr
Page 204:
8. Colson G, Raboult L, Lavelle F,
show all

Download (8Mb) - Etheses - Saurashtra University

Create successful ePaper yourself

Delete template?

Save as template?