| Quassinoids | CHEMONTID:0002119 | A group of compounds chemically degraded from triterpenes. According to their basic skeleton, quassinoids are categorized into five distinct groups, C-18, C-19, C-20, C-22 and C-25 types. The C-20 quassinoids can be further classified into two types, tetracyclic and the pentacyclic. The tetracyclic variety does not have oxygenation at C-20, while the pentacyclic quassinoids possess additional oxygenation at C-20 that allows for the formation of an additional ring. |
| Quaternary ammonium salts | CHEMONTID:0000503 | Compounds containing positively charged polyatomic ion of the structure NR4+, R being an alkyl group or an aryl group. |
| Quaternary benzophenanthridine alkaloids | CHEMONTID:0002669 | Alkaloids containing a quaternary N-demethylbenzophenanthridine skeleton, where the nitrogen atom of the phenanthridine moiety is part of four bonds. |
| Quebrachamine alkaloids | CHEMONTID:0002757 | Alkaloids with a structure based on the quebrachamine skeleton, a tetracyclic compound that is derived by fission of the 7,21 bond of the aspidospermidine skeleton. Some quebrachamine alkaloids lack the C-16 methoxycarbonyl group. |
| Quinacridines | CHEMONTID:0001728 | Compounds containing a quinacridine moiety, which consists of a quinoline fused to an acridine. |
| Quinacridones | CHEMONTID:0001809 | Compounds containing a quinacridone skeleton, which consists of a quinoline fused to an acridone. |
| Quinazolinamines | CHEMONTID:0002314 | Heterocyclic aromatic compounds containing a quianazoline moiety substituted by one or more amine groups. |
| Quinazolines | CHEMONTID:0000485 | Compounds containing a quinazoline moiety, which is made up of two fused six-member aromatic rings, a benzene ring and a pyrimidine ring. |
| Quindolines | CHEMONTID:0004168 | Organic compounds containing an indole and a quinoline, where the pyrrole moiety of the indole is fused to the pyridine moiety of the quinoline. |
| Quinic acids and derivatives | CHEMONTID:0002512 | Compounds containing a quinic acid moiety (or a derivative thereof), which is a cyclitol made up of a cyclohexane ring that bears four hydroxyl groups at positions 1,3.4, and 5, as well as a carboxylic acid at position 1. |
| Quinodimethanes | CHEMONTID:0001579 | Compounds containing a cyclohexene or cyclohexadiene ring that bears two methylidene groups. |
| Quinolidines | CHEMONTID:0003787 | Organic compounds containing a quinolidine or decahydroquinoline moiety, which is a bicyclic skeleton consisting of a piperidine fused to a cyclohexane ring. |
| Quinoline carboxamides | CHEMONTID:0002553 | Quinolines in which the quinoline ring system is substituted by one or more carboxamide groups. |
| Quinoline carboxylic acids | CHEMONTID:0002552 | Quinolines in which the quinoline ring system is substituted by a carboxyl group at one or more positions. |
| Quinoline quinones | CHEMONTID:0002570 | Quinoline derivative with a structure containing a 5,8-dihydroisoquinoline-5,8-dione skeleton. |
| Quinoline-3-carboxamides | CHEMONTID:0002252 | Quinolines in which the quinoline ring system is substituted by one carboxamide group at the 3-position. |
| Quinoline-3-sulfonamides | CHEMONTID:0001513 | Quinolines in which the quinoline ring system is substituted by one sulfonamide group at the 3-position. |
| Quinolines and derivatives | CHEMONTID:0001253 | Compounds containing a quinoline moiety, which consists of a benzene ring fused to a pyrimidine ring to form benzo[b]azabenzene. |
| Quinolizidines | CHEMONTID:0000221 | Compounds containing a quinolizidine moiety, which is a octahydro-2H-quinolizine derivative. |
| Quinolizidinones | CHEMONTID:0001325 | Compounds containing a quinolizidine moiety which bears a ketone group. |
| Quinolizine carboxylic acids and derivatives | CHEMONTID:0002238 | Compounds containing a carboxylic group attached to a quinolizine moiety. |
| Quinolizines | CHEMONTID:0000222 | Compounds containing a quinolizine moiety, which consists of two fused pyridine rings sharing a nitrogen atom. |
| Quinolo[1,2-a]quinazolines | CHEMONTID:0004333 | Aromatic heterocyclic compounds containing a quinazoline and a quinoline fused to each other in a configuration so that they share a nitrogen atom. |
| Quinolones and derivatives | CHEMONTID:0000056 | Compounds containing a quinoline moiety which bears a ketone group. |
| Quinomethanes | CHEMONTID:0000125 | Organic compounds containing a cyclohexene or cyclohexadiene ring that bears a methylidene group and a ketone group. Isomers include m-quinomethane (6-methylidenecyclohex-2-en-1-one), o-quinomethane (5-methylidenecyclohex-2-en-1-one), and p-quinomethane (4-methylidenecyclohexa-2,5-dien-1-one). |
| Quinone and hydroquinone lipids | CHEMONTID:0001534 | Lipids structurally characterized by the presence of a quinone or hydroquinone moiety. |
| Quinones | CHEMONTID:0002495 | Compounds having a fully conjugated cyclic dione structure, such as that of benzoquinones, derived from aromatic compounds by conversion of an even number of number of -CH= groups into -C(=O)- groups with any necessary rearrangement of double bonds (polycyclic and heterocyclic analogues are included). |
| Quinonimines | CHEMONTID:0002892 | Imines derived from quinones by replacement of one or both oxygens by =NR. |
| Quinoxalines | CHEMONTID:0000486 | Compounds containing a quinoxaline moiety, a bicyclic heterocycle made up of a benzene ring fused to a pyrazine ring. |
| Quinuclidines | CHEMONTID:0000252 | Compounds containing a 1-azabicyclo[2.2.2]octane moiety. |
| Quinuclidones | CHEMONTID:0001805 | Compounds containing a quinuclidine moiety which bears a ketone group. |