INDEX
685
S-glycosides, natural 476
hydrolysis, acid-catalysed 476
hydrolysis, enzymic 476
natural 476
synthesis 474, 478
Glycyrrhetic acid, structure 488
Glycyrrhizic acid, structure 488
Glycyrrhizin, structure 488
Gossypol, torsional asymmetry 94
Grignard reagents
addition to conjugated carbonyl derivatives
395
formation 204, 240
as nucleophile with aldehydes and ketones
240
as nucleophile with carboxylic acid
derivatives 271
as nucleophile in S N 1 and S N 2 reactions
204
in tamoxifen synthesis 213
Griseofulvin
as spiro compound 93, 107
structure 385
Groove
major, DNA 553
minor, DNA 553
Ground state 25
Guanidines, basicity 141
Guanidino substituent, in streptomycin 493
Guanine
acidity 450
basicity 449
hydrogen bonding 51
metabolism 451
in nucleic acids 550
tautomerism 449
Guanosine, structure 550
Gulonic acid, in vitamin C biosynthesis 490
Gulose
Fischer projection 104
structure and stereochemistry 465
Haem, structure 424
Half-chair conformation
cyclohexene 67
tetrahydronaphthalene 67
Halide, as nucleophile in S N1 and SN2
reactions 198
Halogens
addition to alkenes 286–92
stereochemistry 287
Halogen radicals 320
Halogenation
of aldehydes and ketones 356
involving enols and enolate anions, rate of
reaction 356
radical 322
Halohydrins
from alkenes 289
formation of epoxides 289
in semi-synthesis of corticosteroids 291
Halonium ion, in addition of halogens to
alkenes 287
Hantzsch pyridine synthesis 458
Harmine, structure 448
Haworth representation, sugars 472
α-Helix, in proteins 511
Hemiacetals
cyclic, sugars 468
conformation 472
decomposition, acid-catalysed 225
base-catalysed 225
formation, acid-catalysed 224
base-catalysed 225
formation, intramolecular 225
sugars, from Fischer projections 104, 468
Hemiacetal–hydroxyaldehyde equilibria,
Table 226
Hemiketals
cyclic, sugars 468
conformation 472
formation, intramolecular 225
Hemithioacetal
formation 235
in glycolysis 582
Hemithioketal formation 235
Henderson–Hasselbalch equation 149–52
buffer solutions 153
calculation of percentage ionization 150
for histidine 434
ionization of drugs 164
ionization of morphine 163
Heparin, structure 496
Heteroatoms, definition 403
Heteroaromaticity 405
Heterocycles
aromatic 44
conformations 72
definition 403
fused 448–50
fused to benzene ring 438–46
nomenclature 438–9
nitrogen, basicity 143
non-aromatic 403–5
as bases 404
as solvents 404
nomenclature 403
numbering 404
synthetic approaches 403
Heterocycle synthesis
approaches
aromatic 457
non-aromatic 403
Bischler–Napieralski isoquinoline 459
C–C bond formation 457
Fischer indole 461
Hantzsch pyridine 458
Knorr pyrrole 460
N–C bond formation 457
Paal–Knorr pyrrole 461
Pictet–Spengler tetrahydroisoquinoline 460
Skraup quinoline 458
Heterolytic cleavage 319
Hexachlorocyclohexane, see lindane
Hexokinase, in glycolysis 579
Hexoses, definition 463
Histamine
formation from histidine 435, 601
receptors 435
Histidine
acid–base properties 434
decarboxylation to histamine 435, 601
as general acid–base 518
as general base catalyst 434
ionization 502, 517
at pH 7 152
structure and pK a values 500
tautomerism 433
Histidine decarboxylase 435
HMG-CoA (β-hydroxy-β-methylglutaryl-CoA)
381
HMG-CoA reductase
in mevalonic acid biosynthesis 381
inhibitors 382
Hofmann elimination 209
quaternary ammonium salts 210
Homolytic cleavage 319
5-HT, see 5-hydroxytryptamine
H¨ uckel’s rule
aromaticity 42
pyridine 405
Hybrid orbitals
carbon 26–33
carbon sp 30
carbon sp
2 28–30
carbon sp
3 26–8
nitrogen sp
3 33
oxygen sp
3 33
Hybridization,
of atomic orbitals 26–35
bond angles 51, 55
bond lengths 31, 51
effect, basicity pyridine 408
influence on acidity 128
influence on basicity 138
Hydrates, aldehydes and ketones 234
Hydration
alkenes 285
alkynes 293
Hydrazine, in nucleic acid sequencing 564
Hydride
anion 169
migration 216
as nucleophile in S N 1 and S N 2 reactions
205
as nucleophile, reduction of aldehydes and
ketones 235
as nucleophile, reduction of carboxylic acid
derivatives 267–9
as nucleophile, reduction of imines 246
shift, in steroid side-chain biosynthesis 295
as strong base, enolate anions 358
Hydrides, complex metal 205, 235, 267
Hydrindane
cis and trans forms 109
cis, conformations 110
Hydrocarbons, nomenclature 7
Hydrocortisone, structure 292
Hydrogen atom, atomic orbital, see atomic
orbitals
Hydrogen bonds 49–51
in acetylacetone 50
in alcohols 50
amines, effect on basicity 137
base pairs in nucleic acids 551
in carboxylic acids 50
in decarboxylation of gem-diacids 390
in decarboxylation of β-ketoacids 388
in DNA 50
in enol forms 348
intermolecular 50
intramolecular 50, 133
685
S-glycosides, natural 476
hydrolysis, acid-catalysed 476
hydrolysis, enzymic 476
natural 476
synthesis 474, 478
Glycyrrhetic acid, structure 488
Glycyrrhizic acid, structure 488
Glycyrrhizin, structure 488
Gossypol, torsional asymmetry 94
Grignard reagents
addition to conjugated carbonyl derivatives
395
formation 204, 240
as nucleophile with aldehydes and ketones
240
as nucleophile with carboxylic acid
derivatives 271
as nucleophile in S N 1 and S N 2 reactions
204
in tamoxifen synthesis 213
Griseofulvin
as spiro compound 93, 107
structure 385
Groove
major, DNA 553
minor, DNA 553
Ground state 25
Guanidines, basicity 141
Guanidino substituent, in streptomycin 493
Guanine
acidity 450
basicity 449
hydrogen bonding 51
metabolism 451
in nucleic acids 550
tautomerism 449
Guanosine, structure 550
Gulonic acid, in vitamin C biosynthesis 490
Gulose
Fischer projection 104
structure and stereochemistry 465
Haem, structure 424
Half-chair conformation
cyclohexene 67
tetrahydronaphthalene 67
Halide, as nucleophile in S N1 and SN2
reactions 198
Halogens
addition to alkenes 286–92
stereochemistry 287
Halogen radicals 320
Halogenation
of aldehydes and ketones 356
involving enols and enolate anions, rate of
reaction 356
radical 322
Halohydrins
from alkenes 289
formation of epoxides 289
in semi-synthesis of corticosteroids 291
Halonium ion, in addition of halogens to
alkenes 287
Hantzsch pyridine synthesis 458
Harmine, structure 448
Haworth representation, sugars 472
α-Helix, in proteins 511
Hemiacetals
cyclic, sugars 468
conformation 472
decomposition, acid-catalysed 225
base-catalysed 225
formation, acid-catalysed 224
base-catalysed 225
formation, intramolecular 225
sugars, from Fischer projections 104, 468
Hemiacetal–hydroxyaldehyde equilibria,
Table 226
Hemiketals
cyclic, sugars 468
conformation 472
formation, intramolecular 225
Hemithioacetal
formation 235
in glycolysis 582
Hemithioketal formation 235
Henderson–Hasselbalch equation 149–52
buffer solutions 153
calculation of percentage ionization 150
for histidine 434
ionization of drugs 164
ionization of morphine 163
Heparin, structure 496
Heteroatoms, definition 403
Heteroaromaticity 405
Heterocycles
aromatic 44
conformations 72
definition 403
fused 448–50
fused to benzene ring 438–46
nomenclature 438–9
nitrogen, basicity 143
non-aromatic 403–5
as bases 404
as solvents 404
nomenclature 403
numbering 404
synthetic approaches 403
Heterocycle synthesis
approaches
aromatic 457
non-aromatic 403
Bischler–Napieralski isoquinoline 459
C–C bond formation 457
Fischer indole 461
Hantzsch pyridine 458
Knorr pyrrole 460
N–C bond formation 457
Paal–Knorr pyrrole 461
Pictet–Spengler tetrahydroisoquinoline 460
Skraup quinoline 458
Heterolytic cleavage 319
Hexachlorocyclohexane, see lindane
Hexokinase, in glycolysis 579
Hexoses, definition 463
Histamine
formation from histidine 435, 601
receptors 435
Histidine
acid–base properties 434
decarboxylation to histamine 435, 601
as general acid–base 518
as general base catalyst 434
ionization 502, 517
at pH 7 152
structure and pK a values 500
tautomerism 433
Histidine decarboxylase 435
HMG-CoA (β-hydroxy-β-methylglutaryl-CoA)
381
HMG-CoA reductase
in mevalonic acid biosynthesis 381
inhibitors 382
Hofmann elimination 209
quaternary ammonium salts 210
Homolytic cleavage 319
5-HT, see 5-hydroxytryptamine
H¨ uckel’s rule
aromaticity 42
pyridine 405
Hybrid orbitals
carbon 26–33
carbon sp 30
carbon sp
2 28–30
carbon sp
3 26–8
nitrogen sp
3 33
oxygen sp
3 33
Hybridization,
of atomic orbitals 26–35
bond angles 51, 55
bond lengths 31, 51
effect, basicity pyridine 408
influence on acidity 128
influence on basicity 138
Hydrates, aldehydes and ketones 234
Hydration
alkenes 285
alkynes 293
Hydrazine, in nucleic acid sequencing 564
Hydride
anion 169
migration 216
as nucleophile in S N 1 and S N 2 reactions
205
as nucleophile, reduction of aldehydes and
ketones 235
as nucleophile, reduction of carboxylic acid
derivatives 267–9
as nucleophile, reduction of imines 246
shift, in steroid side-chain biosynthesis 295
as strong base, enolate anions 358
Hydrides, complex metal 205, 235, 267
Hydrindane
cis and trans forms 109
cis, conformations 110
Hydrocarbons, nomenclature 7
Hydrocortisone, structure 292
Hydrogen atom, atomic orbital, see atomic
orbitals
Hydrogen bonds 49–51
in acetylacetone 50
in alcohols 50
amines, effect on basicity 137
base pairs in nucleic acids 551
in carboxylic acids 50
in decarboxylation of gem-diacids 390
in decarboxylation of β-ketoacids 388
in DNA 50
in enol forms 348
intermolecular 50
intramolecular 50, 133