M. Pharm Pharmaceutical Chemistry ppt on Organic chemistry first semester strategies to synthesize heterocyclic rings A presentation on heterocyclic chemistry
Strategies to synthesize 5 & 6 membered heterocyclic.pptx
1. STRATEGIES TO SYNTHESIZE 5 & 6
MEMBERED HETEROCYCLIC RINGS
PRESENTED BY: PRESENTED TO:
PRABHJOT KAUR DR. SANT KUMAR VERMA
M. PHARMACY ( I SEM) ASSOCIATE PROFESSOR
(PH. CHEMISTRY) (DEPTT. OF PH. CHEMISTRY)
3. HETEROCYCLIC COMPOUNDS
• The word comes from a greek word ‘heteros’ meaning ‘different’.
• Heterocyclic compounds are those where one or more atom(s) of the ring are
heteroatoms such as N, O, P, S, etc.
• More than half of the known organic compounds are heterocyclic compounds.
• For example- Nucleic acid bases, haemoglobin, chlorophyll, vitamins, amino acids,
etc.
6. FIVE MEMBERED HETEROCYCLES
• The simplest of the five membered rings are Pyrrole, Furan and Thiophene.
• Characterized by high degree of reactivity towards substitution by electrophilic
reagents rather than addition.
• From molecular orbital standpoint, these molecules are described as consisting of
planar pentagon with sp2 hybridised carbon atom.
8. 2. The Hantzsch synthesis of Pyrrole
2-oxopropyl propionate 1-chloropropan-2-one
9. 3. Simmons- Smith Reaction for synthesis of Thiophene
(1,1-bis(ethylthio)prop-1-en-2-
yl)(methylene)(phenyl)-l4-oxidane
2-(ethylthio)-4-phenylthiophene
10. SIX MEMBERED HETEROCYCLES
• The methane(-CH=) group in a benzene ring can be replaced by a heteroatom to
generate a six membered heterocyclic compounds.
• The departure from perfectly regular hexagonal geometry caused by the presence
of a hetero atom.
• A strong permanent dipole, traceable to the greater electronegativity of of nitrogen
compared with carbon.