Category:flavoring agents
US / EU / FDA / JECFA / FEMA / FLAVIS / Scholar / Patent Information:
Physical Properties:
Appearance: | colorless to pale yellow clear liquid (est) |
Assay: | 98.00 to 100.00
|
Food Chemicals Codex Listed: | Yes |
Specific Gravity: | 0.95500 to 0.97500 @ 25.00 °C.
|
Pounds per Gallon - (est).: | 7.947 to 8.113
|
Refractive Index: | 1.50700 to 1.51000 @ 20.00 °C.
|
Melting Point: | -23.00 °C. @ 760.00 mm Hg
|
Boiling Point: | 130.00 to 131.00 °C. @ 760.00 mm Hg
|
Vapor Pressure: | 12.234000 mmHg @ 25.00 °C. (est) |
Vapor Density: | 2.31 ( Air = 1 ) |
Flash Point: | 92.00 °F. TCC ( 33.33 °C. )
|
logP (o/w): | 0.750 |
Soluble in: |
| alcohol | | fixed oils | | water, 4.50E+04 mg/L @ 25 °C (exp) |
Organoleptic Properties:
Odor Type: nutty |
sweet warm nutty ethereal |
Odor Description:at 0.10 % in propylene glycol. sweet warm nutty ethereal |
Odor and/or flavor descriptions from others (if found). |
Cosmetic Information:
Suppliers:
Safety Information:
Preferred SDS: View |
European information : |
Most important hazard(s): | T - Toxic. |
R 10 - Flammable. R 20 - Harmful by inhalation. R 25 - Toxic if swallowed. R 41 - Risk of serious damage to eyes. S 01/02 - Keep locked up and out of the reach of children. S 16 - Keep away from sources of ignition - No Smoking. S 20/21 - When using do not eat, drink or smoke. S 23 - Do not breath vapour. S 24/25 - Avoid contact with skin and eyes. S 26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S 36/37/39 - Wear suitable clothing, gloves and eye/face protection. S 45 - In case of accident or if you feel unwell seek medical advice immediately.
|
|
Hazards identification |
|
Classification of the substance or mixture |
GHS Classification in accordance with 29 CFR 1910 (OSHA HCS) |
None found. |
GHS Label elements, including precautionary statements |
|
Pictogram | |
|
Hazard statement(s) |
None found. |
Precautionary statement(s) |
None found. |
Oral/Parenteral Toxicity: |
oral-rabbit LD50 147 mg/kg BEHAVIORAL: MUSCLE CONTRACTION OR SPASTICITY)
BEHAVIORAL: SOMNOLENCE (GENERAL DEPRESSED ACTIVITY)
BEHAVIORAL: CONVULSIONS OR EFFECT ON SEIZURE THRESHOLD Archives Internationales de Pharmacodynamie et de Therapie. Vol. 36, Pg. 387, 1930.
intraperitoneal-rabbit LDLo 150 mg/kg Archives Internationales de Pharmacodynamie et de Therapie. Vol. 36, Pg. 387, 1930.
intraperitoneal-mouse LD50 98 mg/kg Progress in Biochemical Pharmacology. Vol. 1, Pg. 542, 1965.
|
Dermal Toxicity: |
subcutaneous-rabbit LD50 250 mg/kg Archives Internationales de Pharmacodynamie et de Therapie. Vol. 36, Pg. 387, 1930.
subcutaneous-mouse LD50 61 mg/kg "Pesticide Index," Frear, E.H., ed., State College, PA, College Science Pub., 1969Vol. 4, Pg. 335, 1969.
|
Inhalation Toxicity: |
Not determined
|
Safety in Use Information:
Category: | flavoring agents |
Recommendation for pyrrole usage levels up to: | | not for fragrance use.
|
|
Maximised Survey-derived Daily Intakes (MSDI-EU): | 0.11 (μg/capita/day) |
Maximised Survey-derived Daily Intakes (MSDI-USA): | 0.01 (μg/capita/day) |
Structure Class: | I |
Use levels for FEMA GRAS flavoring substances on which the FEMA Expert Panel based its judgments that the substances are generally recognized as safe (GRAS). |
The Expert Panel also publishes separate extensive reviews of scientific information on all FEMA GRAS flavoring substances and can be found at FEMA Flavor Ingredient Library |
publication number: 6 |
Click here to view publication 6 |
| average usual ppm | average maximum ppm |
baked goods: | - | 3.00000 |
beverages(nonalcoholic): | - | - |
beverages(alcoholic): | - | - |
breakfast cereal: | - | 3.00000 |
cheese: | - | - |
chewing gum: | - | - |
condiments / relishes: | - | - |
confectionery froastings: | - | - |
egg products: | - | - |
fats / oils: | - | - |
fish products: | - | - |
frozen dairy: | - | 3.00000 |
fruit ices: | - | 3.00000 |
gelatins / puddings: | - | 3.00000 |
granulated sugar: | - | - |
gravies: | - | 3.00000 |
hard candy: | - | 3.00000 |
imitation dairy: | - | - |
instant coffee / tea: | - | - |
jams / jellies: | - | - |
meat products: | - | 3.00000 |
milk products: | - | - |
nut products: | - | - |
other grains: | - | - |
poultry: | - | - |
processed fruits: | - | - |
processed vegetables: | - | - |
reconstituted vegetables: | - | - |
seasonings / flavors: | - | - |
snack foods: | - | - |
soft candy: | - | - |
soups: | - | 3.00000 |
sugar substitutes: | - | - |
sweet sauces: | - | - |
|
Food categories according to Commission Regulation EC No. 1565/2000 (EC, 2000) in FGE.06 (EFSA, 2002a). According to the Industry the "normal" use is defined as the average of reported usages and "maximum use" is defined as the 95th percentile of reported usages (EFSA, 2002i). |
Note: mg/kg = 0.001/1000 = 0.000001 = 1/1000000 = ppm. |
| average usage mg/kg | maximum usage mg/kg |
Dairy products, excluding products of category 02.0 (01.0): | 3.00000 | 3.00000 |
Fats and oils, and fat emulsions (type water-in-oil) (02.0): | - | - |
Edible ices, including sherbet and sorbet (03.0): | 3.00000 | 3.00000 |
Processed fruit (04.1): | - | - |
Processed vegetables (incl. mushrooms & fungi, roots & tubers, pulses and legumes), and nuts & seeds (04.2): | - | - |
Confectionery (05.0): | 3.00000 | 3.00000 |
Chewing gum (05.3): | - | - |
Cereals and cereal products, incl. flours & starches from roots & tubers, pulses & legumes, excluding bakery (06.0): | 3.00000 | 3.00000 |
Bakery wares (07.0): | 3.00000 | 3.00000 |
Meat and meat products, including poultry and game (08.0): | - | - |
Fish and fish products, including molluscs, crustaceans and echinoderms (MCE) (09.0): | - | - |
Eggs and egg products (10.0): | - | - |
Sweeteners, including honey (11.0): | - | - |
Salts, spices, soups, sauces, salads, protein products, etc. (12.0): | - | - |
Foodstuffs intended for particular nutritional uses (13.0): | - | - |
Non-alcoholic ("soft") beverages, excl. dairy products (14.1): | - | - |
Alcoholic beverages, incl. alcohol-free and low-alcoholic counterparts (14.2): | - | - |
Ready-to-eat savouries (15.0): | - | - |
Composite foods (e.g. casseroles, meat pies, mincemeat) - foods that could not be placed in categories 01.0 - 15.0 (16.0): | - | - |
Safety References:
European Food Safety Athority(EFSA):Flavor usage levels; Subacute, Subchronic, Chronic and Carcinogenicity Studies; Developmental / Reproductive Toxicity Studies; Genotoxicity Studies...
|
European Food Safety Authority (EFSA) reference(s):
|
Opinion of the Scientific Panel on food additives, flavourings, processing aids and materials in contact with food (AFC) related to Flavouring Group Evaluation 24 (FGE.24): Pyridine, pyrrole, indole and quinoline derivatives from chemical group 28 (Commission Regulation (EC) No 1565/2000 of 18 July 2000) View page or View pdf
|
Pyridine, pyrrole, indole and quinoline derivatives from chemical group 28 Flavouring Group Evaluation 24, Revision 1 - Scientific Opinion of the Panel on Food Additives, Flavourings, Processing Aids and Materials in contact with Food (AFC) View page or View pdf
|
Flavouring Group Evaluation 77 (FGE77) [1] - Consideration of Pyridine, Pyrrole and Quinoline Derivatives evaluated by JECFA (63rd meeting) structurally related to Pyridine, Pyrrole, Indole and Quinoline Derivatives evaluated by EFSA in FGE.24Rev1 (2008) View page or View pdf
|
Statement on List of Representative Substances for Testing.
The current Statement lays down a list of substances in sub-groups with representative substances for which additional data are required prior to their evaluation through the Procedure (Regulation (EC) No 1565/2000). View page or View pdf
|
Scientific Opinion on Flavouring Group Evaluation 77, Revision 2 (FGE.77Rev2): Consideration of Pyridine, Pyrrole and Quinoline Derivatives evaluated by JECFA (63rd meeting) structurally related to Pyridine, Pyrrole, Indole and Quinoline Derivatives evaluated by EFSA in FGE.24Rev2 (2013) View page or View pdf
|
Scientific opinion on flavouring group evaluation 77, revision 3 (FGE.77Rev3): consideration of pyridine, pyrrole and quinoline derivatives evaluated by JECFA (63rd meeting) structurally related to pyridine, pyrrole, indole and quinoline derivatives evaluated by EFSA in FGE.24Rev2 View page or View pdf
|
EPI System: View |
ClinicalTrials.gov:search |
Daily Med:search |
Chemical Carcinogenesis Research Information System:Search |
AIDS Citations:Search |
Cancer Citations:Search |
Toxicology Citations:Search |
EPA Substance Registry Services (TSCA):109-97-7 |
EPA ACToR:Toxicology Data |
EPA Substance Registry Services (SRS):Registry |
Laboratory Chemical Safety Summary :8027 |
National Institute of Allergy and Infectious Diseases:Data |
WISER:UN 1992 |
WGK Germany:2 |
1H-pyrrole |
Chemidplus:0000109977 |
RTECS:UX9275000 for cas# 109-97-7 |
References:
Other Information:
Potential Blenders and core components note
For Odor |
No odor group found for these |
sulfuryl octanoate FL/FR |
|
carbitol CS |
sulfuryl butyrate FL/FR |
sulfuryl decanoate FL/FR |
sulfuryl hexanoate FL/FR |
sulfuryl isobutyrate FL/FR |
sulfuryl propionate FL/FR |
valeraldehyde dibutyl acetal FL/FR |
valeraldehyde propylene glycol acetal FL/FR |
alcoholic |
alcoholic |
3- hexanol FL/FR |
balsamic |
propyl benzoate FL/FR |
bready |
coffee furanone FL/FR |
buttery |
acetyl propionyl FL/FR |
butyl octanoate FL/FR |
3,4- hexane dione FL/FR |
camphoreous |
bornyl isobutyrate FL/FR |
caramellic |
ethyl 2-hydroxy-2-methyl butyrate FL/FR |
chemical |
iso butyl formate FL/FR |
chocolate |
chocolate pyrazine A FL/FR |
2,5- dimethyl pyrazine FL/FR |
2- methoxypyrazine FL/FR |
cocoa |
2- methyl butyraldehyde FL/FR |
coconut |
alpha- angelica lactone FL/FR |
gamma- heptalactone FL/FR |
corn chip |
popcorn pyrimidine FL/FR |
coumarinic |
coumane FL/FR |
tonka bean resinoid FR |
earthy |
2- ethyl-3-methoxypyrazine FL/FR |
ethereal |
acetal FL/FR |
acetaldehyde dimethyl acetal FL/FR |
iso amyl acetoacetate FL/FR |
iso butyl alcohol FL/FR |
cyclohexyl formate FL/FR |
decyl propionate FL/FR |
ethyl acetate FL/FR |
ethyl formate FL/FR |
ethyl pyruvate FL/FR |
1- hexen-3-ol FL/FR |
methyl acetate FL/FR |
methyl ethyl ketone FL/FR |
(E)- methyl tiglate FL/FR |
2- methyl valeraldehyde FL/FR |
3- pentanone FL/FR |
iso propyl acetate FL/FR |
iso propyl formate FL/FR |
propyl formate FL/FR |
propyl valerate FL/FR |
iso valeraldehyde propylene glycol acetal FL/FR |
fatty |
coconut absolute FL/FR |
fermented |
valeraldehyde FL/FR |
floral |
alpha- amyl cinnamaldehyde diethyl acetal FR |
boronia butenal FR |
para- cresyl laurate FL/FR |
ortho- methyl acetophenone FL/FR |
fruity |
acetaldehyde diisoamyl acetal FL/FR |
allyl 2-ethyl butyrate FL/FR |
amyl acetate FL/FR |
amyl formate FL/FR |
amyl heptanoate FL/FR |
iso amyl nonanoate FL/FR |
benzyl methyl ether FL/FR |
iso butyl acetate FL/FR |
iso butyl propionate FL/FR |
2- ethyl butyl acetate FL/FR |
(E,E)- ethyl sorbate FL/FR |
methyl hexanoate FL/FR |
methyl valerate FL/FR |
3- methyl-2-butenal FL/FR |
2- pentanone FL/FR |
iso propenyl acetate FL/FR |
iso propyl 2-methyl butyrate FL/FR |
iso propyl butyrate FL/FR |
iso propyl propionate FL/FR |
iso propyl valerate FL/FR |
tetrahydrofurfuryl acetate FL/FR |
tropical thiazole FL/FR |
green |
iso amyl formate FL/FR |
2- heptyl furan FL/FR |
(E,Z)-2,6- nonadien-1-yl acetate FL/FR |
(Z)-2- penten-1-ol FL/FR |
tiglaldehyde FL/FR |
herbal |
hexanol FL/FR |
saffron pyranone FR |
musty |
2- acetyl pyrrole FL/FR |
3- acetyl-2,5-dimethyl furan FL/FR |
hazelnut pyrazine FL/FR |
menthofuran FL/FR |
naphthyl |
ortho- methyl anisole FL/FR |
para- methyl anisole FL/FR |
nutty |
3- acetyl pyridine FL/FR |
2- acetyl-3-ethyl pyrazine FL/FR |
2- acetyl-3-methyl pyrazine FL/FR |
2- acetyl-3,5-dimethyl pyrazine FL/FR |
2- acetyl-5-methyl furan FL/FR |
3,6- cocoa pyrazine FL/FR |
3,5- cocoa pyrazine FL/FR |
2,3- dimethyl pyrazine FL/FR |
4,5- dimethyl-2-ethyl-3-thiazoline FL/FR |
2- ethyl pyrazine FL/FR |
2- ethyl-4-methyl thiazole FL/FR |
filbert heptenone FL/FR |
filbert pyrazine FL/FR |
2,6- lutidine FL/FR |
maraniol CS |
2- methyl pyrazine FL/FR |
5- methyl quinoxaline FL/FR |
2- methyl thio-3,5 or 6-methyl pyrazine FL/FR |
2- methyl-3-(methyl thio) pyrazine FL/FR |
2- methyl-3-ethoxypyrazine FL/FR |
2- methyl-3-propyl pyrazine FL/FR |
nutty cyclohexenone FL/FR |
nutty quinoxaline FL/FR |
ortho- salicylic acid CS |
shoyu pyrazine FL/FR |
2,3,5,6- tetramethyl pyrazine FL/FR |
2,4,5- trimethyl oxazole FL/FR |
2,3,5- trimethyl pyrazine FL/FR |
vinyl sulfurol FL/FR |
phenolic |
anisole FL/FR |
popcorn |
2- acetyl pyrazine FL/FR |
2- acetyl thiazole FL/FR |
spicy |
3-(2- furyl) acrolein FL/FR |
sulfurous |
benzothiazole FL/FR |
furfuryl thioacetate FL/FR |
tobacco |
veltonal (Bedoukian) FR |
tonka |
coumarin FR |
tonka bean absolute FR |
whiskey lactone FL/FR |
woody |
sandalwood oil FL/FR |
For Flavor |
No flavor group found for these |
acetaldehyde 1,3-octane diol acetal FL |
acetaldehyde diisoamyl acetal FL/FR |
acetone FL |
acetyl acetaldehyde dimethyl acetal FL |
bornyl isobutyrate FL/FR |
butyl methyl ketone FL |
butyl octanoate FL/FR |
butyramide FL |
chocolate pyrazine A FL/FR |
chocolate pyrazine B FL |
coumane FL/FR |
cyclohexyl methyl pyrazine FL |
decyl propionate FL/FR |
diethyl sulfide FL |
2,5- diethyl thiazole FL |
2,5- diethyl-4-methyl thiazole FL |
6,7- dihydro-2,3-dimethyl-5H-cyclopentapyrazine FL |
dimethyl dihydrocyclopentapyrazine FL |
2,5- dimethyl thiazole FL |
ethanol FL |
ethyl 2-hydroxy-2-methyl butyrate FL/FR |
2- ethyl-3-methoxypyrazine FL/FR |
(Z+E)-5- ethyl-4-methyl-2-(2-butyl) thiazoline FL |
(Z+E)-5- ethyl-4-methyl-2-(2-methyl propyl) thiazoline FL |
3-(2- furyl) acrolein FL/FR |
(E,E)-2,4- heptadien-1-ol FL |
2- heptenoic acid FL |
2- hexyl-5 or 6-keto-1,4-dioxane FL |
2- methoxypyrazine FL/FR |
methyl 2-(methyl thio) acetate FL |
S-( methyl thio) hexanoate FL |
(E)- methyl tiglate FL/FR |
2- methyl-3-(methyl thio) pyrazine FL/FR |
2- methyl-3-ethoxypyrazine FL/FR |
peanut dithiazine FL |
3- pentanone FL/FR |
2- propyl pyridine FL |
propyl valerate FL/FR |
iso propyl valerate FL/FR |
pyrazines mixture FL |
pyrazinyl methyl sulfide FL |
para- salicylic acid FL |
sulfuryl butyrate FL/FR |
sulfuryl decanoate FL/FR |
sulfuryl hexanoate FL/FR |
sulfuryl isobutyrate FL/FR |
thiazole FL |
valeraldehyde propylene glycol acetal FL/FR |
|
5- acetyl-2,3-dihydro-1,4-thiazine FL |
sulfuryl formate FL |
sulfuryl octanoate FL/FR |
sulfuryl propionate FL/FR |
valeraldehyde dibutyl acetal FL/FR |
alcoholic |
alcoholic |
3- hexanol FL/FR |
alliaceous |
2- methyl thioacetaldehyde FL |
tropical thiazole FL/FR |
anisic |
ortho- methyl acetophenone FL/FR |
aromatic |
anisole FL/FR |
bready |
2- propionyl thiazole FL |
brown |
tetrahydrofurfuryl acetate FL/FR |
burnt |
2- methyl quinoxaline FL |
2,4,5- trimethyl oxazole FL/FR |
buttery |
butyroin FL |
3,4- hexane dione FL/FR |
camphoreous |
ortho- methyl anisole FL/FR |
caramellic |
pyruvaldehyde FL |
chemical |
2,5- dimethyl furan FL |
methyl ethyl ketone FL/FR |
cocoa |
2- methyl furan FL |
coffee |
difurfuryl ether FL |
2- ethyl-4-methyl thiazole FL/FR |
2-iso propyl pyrazine FL |
corn chip |
2- acetyl thiazole FL/FR |
2- acetyl-2-thiazoline FL |
popcorn pyrimidine FL/FR |
creamy |
alpha- angelica lactone FL/FR |
earthy |
2- methyl-3-propyl pyrazine FL/FR |
ethereal |
acetaldehyde dimethyl acetal FL/FR |
allyl 2-ethyl butyrate FL/FR |
iso butyl alcohol FL/FR |
ethyl acetate FL/FR |
ethyl formate FL/FR |
4- hexen-3-one FL |
methyl acetate FL/FR |
iso propenyl acetate FL/FR |
iso propyl acetate FL/FR |
fatty |
coconut absolute FL/FR |
(E,E)-2,4- decadienal FL |
2- heptyl furan FL/FR |
(E,E)-2,4- nonadienal FL |
fishy |
4,5- dimethyl thiazole FL |
fruity |
amyl acetate FL/FR |
iso amyl acetoacetate FL/FR |
amyl formate FL/FR |
amyl heptanoate FL/FR |
benzyl methyl ether FL/FR |
iso butyl acetate FL/FR |
iso butyl propionate FL/FR |
2- ethyl butyl acetate FL/FR |
(E,E)- ethyl sorbate FL/FR |
2,4- hexadien-1-ol FL |
2- methyl allyl butyrate FL |
methyl hexanoate FL/FR |
methyl valerate FL/FR |
3- methyl-2-butenal FL/FR |
2- pentanone FL/FR |
iso propyl 2-methyl butyrate FL/FR |
propyl benzoate FL/FR |
iso propyl butyrate FL/FR |
iso propyl formate FL/FR |
propyl formate FL/FR |
iso propyl propionate FL/FR |
tiglaldehyde FL/FR |
iso valeraldehyde propylene glycol acetal FL/FR |
fusel |
2- methyl butyraldehyde FL/FR |
green |
iso amyl formate FL/FR |
cyclohexyl formate FL/FR |
dihydroxyacetophenone (mixed isomers) FL |
2,5- dimethyl thiophene FL |
2- ethyl butyraldehyde FL |
hexanol FL/FR |
1- hexen-3-ol FL/FR |
4- methyl thiazole FL |
2- methyl-5-isopropyl pyrazine FL |
(E,Z)-2,6- nonadien-1-yl acetate FL/FR |
(Z)-2- penten-1-ol FL/FR |
2- vinyl pyrazine FL |
lactonic |
gamma- heptalactone FL/FR |
meaty |
benzothiazole FL/FR |
musty |
2,5- dimethyl pyrazine FL/FR |
2- ethoxythiazole FL |
hazelnut pyrazine FL/FR |
menthofuran FL/FR |
propionaldehyde FL |
shoyu pyrazine FL/FR |
2,3,5- trimethyl pyrazine FL/FR |
naphthyl |
para- methyl anisole FL/FR |
nutty |
acetal FL/FR |
3- acetyl pyridine FL/FR |
2- acetyl pyrrole FL/FR |
3- acetyl-2,5-dimethyl furan FL/FR |
2- acetyl-3-ethyl pyrazine FL/FR |
2- acetyl-3-methyl pyrazine FL/FR |
2- acetyl-3,5-dimethyl pyrazine FL/FR |
2- acetyl-5-methyl furan FL/FR |
aconitic acid FL |
3,6- cocoa pyrazine FL/FR |
3,5- cocoa pyrazine FL/FR |
coffee furanone FL/FR |
3,5- diethyl-2-methyl pyrazine FL |
2,5- diethyl-3-methyl pyrazine FL |
2,3- dimethyl pyrazine FL/FR |
4,5- dimethyl-2-ethyl-3-thiazoline FL/FR |
2,4- dimethyl-5-vinyl thiazole FL |
2- ethyl pyrazine FL/FR |
1- ethyl-2-acetyl pyrrole FL |
filbert heptenone FL/FR |
filbert pyrazine FL/FR |
european hazelnut oleoresin FL |
2,6- lutidine FL/FR |
2- methyl pyrazine FL/FR |
5- methyl quinoxaline FL/FR |
2- methyl thio-3,5 or 6-methyl pyrazine FL/FR |
nutty cyclohexenone FL/FR |
nutty quinoxaline FL/FR |
nutty thiazole FL |
peanut oxazole FL |
2,3,5,6- tetramethyl pyrazine FL/FR |
vinyl sulfurol FL/FR |
popcorn |
2- propionyl-2-thiazoline FL |
pungent |
acetaldehyde FL |
roasted |
2- acetyl pyrazine FL/FR |
furfuryl thioacetate FL/FR |
rummy |
iso butyl formate FL/FR |
ethyl pyruvate FL/FR |
toasted |
acetyl propionyl FL/FR |
vegetable |
2- methyl valeraldehyde FL/FR |
waxy |
para- cresyl laurate FL/FR |
winey |
iso amyl nonanoate FL/FR |
5- ethyl-2-methyl pyridine FL |
valeraldehyde FL/FR |
woody |
sandalwood oil FL/FR |
whiskey lactone FL/FR |
Potential Uses:
Occurrence (nature, food, other): note
Synonyms:
| azole | 1-aza-2,4- | cyclopentadiene | | divinylene imine | | divinyleneimine | | imidole | | parzate | 1H- | pyrrole | mono | pyrrole | | pyrrole pharma grade |
Articles:
|
Flavouring ingredient
Pyrrole has very low basicity compared to conventional amines and some other aromatic compounds like pyridine. This decreased basicity is attributed to the delocalization of the lone pair of electrons of the nitrogen atom in the aromatic ring. Pyrrole is a very weak base with a pKaH of about ?4. Protonation results in loss of aromaticity, and is, therefore, unfavorable.; Pyrrole is a heterocyclic aromatic organic compound, a five-membered ring with the formula C4H4NH. Substituted derivatives are also called pyrroles. For example, C4H4NCH3 is N-methylpyrrole. Porphobilinogen is a trisubstituted pyrrole, which is the biosynthetic precursor to many natural products.; The starting materials in the Piloty-Robinson pyrrole synthesis are 2 equivalents of an aldehyde and hydrazine. The product is a pyrrole with specific substituents in the 3 and 4 positions. The aldehyde reacts with the diamine to an intermediate di-imine (R?C=N?N=C?R), which, with added hydrochloric acid, gives ring-closure and loss of ammonia to the pyrrole.
|