CAS No. :	2022-85-7
Formula :	C₄H₄FN₃O
M.W :	129.09
SMILES Code :	O=C1NC(=C(F)C=N1)N
Synonyms :	Flucytosine; NSC 103805; Flucytosine, 5-fluorocytosine, Flucytosin, Ancobon, Ancotil
MDL No. :	MFCD00006035
InChI Key :	XRECTZIEBJDKEO-UHFFFAOYSA-N
Pubchem ID :	3366

GHS Pictogram:
Signal Word:	Warning
Hazard Statements:	H302
Precautionary Statements:	P280-P305+P351+P338

H9 human embryonic stem cells	50 µM	36 h	To verify the cytotoxic effect of 5-FC on H9 human embryonic stem cells, results showed no significant toxicity at 50 µM concentration	Exp Mol Med. 2019 Jul 19;51(7):1-12
293T cells	50 µM	48 h	To verify the cytotoxic effect of 5-FC on 293T cells, results showed no significant toxicity at 50 µM concentration	Exp Mol Med. 2019 Jul 19;51(7):1-12
R3327-AT cells	100 µg/ml	24 h	To evaluate the cytotoxicity of 5-FC and 5-FU on R3327-AT cells. Results showed that CDUPRT-expressing cells were more sensitive to 5-FC and 5-FU than CD-expressing cells.	Radiother Oncol. 2009 Sep;92(3):345-52
T24 bladder epithelial cells	10 µg/mL	30 min	To evaluate the effect of 5-FC on KTE223 strain adhesion to bladder epithelial cells. Results showed that 5-FC reduced adhesion in a dose-dependent manner and slightly increased epithelial cell survival.	Antimicrob Agents Chemother. 2025 Apr 3;69(5):e0028025
KTE223 UPEC strain	2.5 µg/mL	24 h	To assess the effect of 5-FC on virulence factor expression in the KTE223 strain. Results showed that 5-FC significantly inhibited the expression of csgB and csgD genes, indicating its impact on biofilm formation through pyrimidine starvation.	Antimicrob Agents Chemother. 2025 Apr 3;69(5):e0028025
Uropathogenic Escherichia coli (UPEC) clinical isolates	2.5 µg/mL	24 h	To evaluate the effect of 5-FC on biofilm formation and adhesion in UPEC strains. Results showed that 5-FC significantly reduced biofilm adhesion of UPEC clinical isolates at both 30°C and 37°C.	Antimicrob Agents Chemother. 2025 Apr 3;69(5):e0028025
HB1.F3.CD cells	1, 10, 100 µg/mL	4 days	To evaluate the effect of 5-FC on CD-expressing stem cell growth, results showed significant inhibition of HB1.F3.CD cell growth	Cancer Sci. 2010 Apr;101(4):955-62
SKOV-3 cells	1, 10, 100 µg/mL	4 days	To evaluate the effect of 5-FC on ovarian cancer cell growth, results showed no significant inhibition of SKOV-3 cell growth at tested concentrations	Cancer Sci. 2010 Apr;101(4):955-62
MCF-7 human breast cancer cells	2 mM	72 h	To investigate the cytotoxicity of 5-FC in the presence of UC-ACD on MCF-7 cells.	ACS Nano. 2022 Oct 25;16(10):15873-15883
Caco-2 human colorectal cancer cells	2 mM	72 h	To investigate the cytotoxicity of 5-FC in the presence of UC-ACD (conjugates of upconversion nanoparticles and anti-EGFR affibody-cytosine deaminase fusion proteins) on Caco-2 cells.	ACS Nano. 2022 Oct 25;16(10):15873-15883
Human prostate carcinoma cells DU145	0–30mM	6 days	To evaluate the sensitivity of DU145 cells transfected with wild-type and mutant bCD to 5FC, results showed that mutant bCD-transfected cells were 2.1–5-fold more sensitive to 5FC than wild-type.	Cancer Res. 2009 Jun 1;69(11):4791-9
Human colorectal carcinoma cells HCT116	0–30mM	6 days	To evaluate the sensitivity of HCT116 cells transfected with wild-type and mutant bCD to 5FC, results showed that mutant bCD-transfected cells were 2.4–17-fold more sensitive to 5FC than wild-type.	Cancer Res. 2009 Jun 1;69(11):4791-9
Rat C6 glioma cells	0–30mM	6 days	To evaluate the sensitivity of C6 cells transfected with wild-type and mutant bCD to 5FC, results showed that mutant bCD-transfected cells were 1.3–2.7-fold more sensitive to 5FC than wild-type.	Cancer Res. 2009 Jun 1;69(11):4791-9
Cryptococcus gattii VGII	300 mg/mL		To evaluate the adaptation of VGII strains to 5-fluorocytosine, finding that some VGII strains exhibited high adaptation to 5-fluorocytosine	Innovation (Camb). 2024 Jul 31;5(5):100681

Male athymic nu/nu mice	Subcutaneous tumor model	Intravenous injection	150 mg/kg	Single dose, monitored for 2 hours	To monitor the metabolism of 5-FC and 5-FU using 19F MRS. Results showed that CDUPRT expression led to enhanced accumulation of fluorine nucleotide (FNuc) in vivo.	Radiother Oncol. 2009 Sep;92(3):345-52
C57BL/6 mice	Intracerebral infection with Cryptococcus neoformans	Intraperitoneal injection	100 mg/kg	Every other day for 28 days	Evaluate the efficacy of 5-FC combined with Amphotericin B. Results showed that all mice treated with AmpB + 5-FC survived until the end of the experiment, whereas only 33% of mice in the AmpB + PEA group survived.	Antimicrob Agents Chemother. 2023 Oct 18;67(10):e0045923
BALB/c athymic nude mice	Caco-2 tumor model	Oral gavage	10 mg/mL		Evaluate the tumor targeting and 5-FC conversion efficacy of UC-ACD in vivo. Results showed significantly slower tumor growth (2.2±0.04 - 2.5±0.16-fold) in UC-ACD (+)IR treated tumors, with median survival increasing from 28 to 35 days.	ACS Nano. 2022 Oct 25;16(10):15873-15883
Nude mice	HCT116 xenograft tumor model	Intraperitoneal injection	375mg/kg	Twice daily for 21 days	To evaluate the tumor growth inhibition of mutant bCD (1525) in vivo, results showed that 1525-expressing tumors were significantly restricted in growth under 5FC treatment, while wild-type bCD-expressing tumors were unresponsive to the same dose of 5FC.	Cancer Res. 2009 Jun 1;69(11):4791-9

Precautionary Statements-General
Code	Phrase
P101	If medical advice is needed,have product container or label at hand.
P102	Keep out of reach of children.
P103	Read label before use
Prevention
Code	Phrase
P201	Obtain special instructions before use.
P202	Do not handle until all safety precautions have been read and understood.
P210	Keep away from heat/sparks/open flames/hot surfaces. - No smoking.
P211	Do not spray on an open flame or other ignition source.
P220	Keep/Store away from clothing/combustible materials.
P221	Take any precaution to avoid mixing with combustibles
P222	Do not allow contact with air.
P223	Keep away from any possible contact with water, because of violent reaction and possible flash fire.
P230	Keep wetted
P231	Handle under inert gas.
P232	Protect from moisture.
P233	Keep container tightly closed.
P234	Keep only in original container.
P235	Keep cool
P240	Ground/bond container and receiving equipment.
P241	Use explosion-proof electrical/ventilating/lighting/equipment.
P242	Use only non-sparking tools.
P243	Take precautionary measures against static discharge.
P244	Keep reduction valves free from grease and oil.
P250	Do not subject to grinding/shock/friction.
P251	Pressurized container: Do not pierce or burn, even after use.
P260	Do not breathe dust/fume/gas/mist/vapours/spray.
P261	Avoid breathing dust/fume/gas/mist/vapours/spray.
P262	Do not get in eyes, on skin, or on clothing.
P263	Avoid contact during pregnancy/while nursing.
P264	Wash hands thoroughly after handling.
P265	Wash skin thouroughly after handling.
P270	Do not eat, drink or smoke when using this product.
P271	Use only outdoors or in a well-ventilated area.
P272	Contaminated work clothing should not be allowed out of the workplace.
P273	Avoid release to the environment.
P280	Wear protective gloves/protective clothing/eye protection/face protection.
P281	Use personal protective equipment as required.
P282	Wear cold insulating gloves/face shield/eye protection.
P283	Wear fire/flame resistant/retardant clothing.
P284	Wear respiratory protection.
P285	In case of inadequate ventilation wear respiratory protection.
P231 + P232	Handle under inert gas. Protect from moisture.
P235 + P410	Keep cool. Protect from sunlight.
Response
Code	Phrase
P301	IF SWALLOWED:
P304	IF INHALED:
P305	IF IN EYES:
P306	IF ON CLOTHING:
P307	IF exposed:
P308	IF exposed or concerned:
P309	IF exposed or if you feel unwell:
P310	Immediately call a POISON CENTER or doctor/physician.
P311	Call a POISON CENTER or doctor/physician.
P312	Call a POISON CENTER or doctor/physician if you feel unwell.
P313	Get medical advice/attention.
P314	Get medical advice/attention if you feel unwell.
P315	Get immediate medical advice/attention.
P320
P302 + P352	IF ON SKIN: wash with plenty of soap and water.
P321
P322
P330	Rinse mouth.
P331	Do NOT induce vomiting.
P332	IF SKIN irritation occurs:
P333	If skin irritation or rash occurs:
P334	Immerse in cool water/wrap n wet bandages.
P335	Brush off loose particles from skin.
P336	Thaw frosted parts with lukewarm water. Do not rub affected area.
P337	If eye irritation persists:
P338	Remove contact lenses, if present and easy to do. Continue rinsing.
P340	Remove victim to fresh air and keep at rest in a position comfortable for breathing.
P341	If breathing is difficult, remove victim to fresh air and keep at rest in a position comfortable for breathing.
P342	If experiencing respiratory symptoms:
P350	Gently wash with plenty of soap and water.
P351	Rinse cautiously with water for several minutes.
P352	Wash with plenty of soap and water.
P353	Rinse skin with water/shower.
P360	Rinse immediately contaminated clothing and skin with plenty of water before removing clothes.
P361	Remove/Take off immediately all contaminated clothing.
P362	Take off contaminated clothing and wash before reuse.
P363	Wash contaminated clothing before reuse.
P370	In case of fire:
P371	In case of major fire and large quantities:
P372	Explosion risk in case of fire.
P373	DO NOT fight fire when fire reaches explosives.
P374	Fight fire with normal precautions from a reasonable distance.
P376	Stop leak if safe to do so. Oxidising gases (section 2.4) 1
P377	Leaking gas fire: Do not extinguish, unless leak can be stopped safely.
P378
P380	Evacuate area.
P381	Eliminate all ignition sources if safe to do so.
P390	Absorb spillage to prevent material damage.
P391	Collect spillage. Hazardous to the aquatic environment
P301 + P310	IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician.
P301 + P312	IF SWALLOWED: call a POISON CENTER or doctor/physician IF you feel unwell.
P301 + P330 + P331	IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
P302 + P334	IF ON SKIN: Immerse in cool water/wrap in wet bandages.
P302 + P350	IF ON SKIN: Gently wash with plenty of soap and water.
P303 + P361 + P353	IF ON SKIN (or hair): Remove/Take off Immediately all contaminated clothing. Rinse SKIN with water/shower.
P304 + P312	IF INHALED: Call a POISON CENTER or doctor/physician if you feel unwell.
P304 + P340	IF INHALED: Remove victim to fresh air and Keep at rest in a position comfortable for breathing.
P304 + P341	IF INHALED: If breathing is difficult, remove victim to fresh air and keep at rest in a position comfortable for breathing.
P305 + P351 + P338	IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P306 + P360	IF ON CLOTHING: Rinse Immediately contaminated CLOTHING and SKIN with plenty of water before removing clothes.
P307 + P311	IF exposed: call a POISON CENTER or doctor/physician.
P308 + P313	IF exposed or concerned: Get medical advice/attention.
P309 + P311	IF exposed or if you feel unwell: call a POISON CENTER or doctor/physician.
P332 + P313	IF SKIN irritation occurs: Get medical advice/attention.
P333 + P313	IF SKIN irritation or rash occurs: Get medical advice/attention.
P335 + P334	Brush off loose particles from skin. Immerse in cool water/wrap in wet bandages.
P337 + P313	IF eye irritation persists: Get medical advice/attention.
P342 + P311	IF experiencing respiratory symptoms: call a POISON CENTER or doctor/physician.
P370 + P376	In case of fire: Stop leak if safe to Do so.
P370 + P378	In case of fire:
P370 + P380	In case of fire: Evacuate area.
P370 + P380 + P375	In case of fire: Evacuate area. Fight fire remotely due to the risk of explosion.
P371 + P380 + P375	In case of major fire and large quantities: Evacuate area. Fight fire remotely due to the risk of explosion.
Storage
Code	Phrase
P401
P402	Store in a dry place.
P403	Store in a well-ventilated place.
P404	Store in a closed container.
P405	Store locked up.
P406	Store in corrosive resistant/ container with a resistant inner liner.
P407	Maintain air gap between stacks/pallets.
P410	Protect from sunlight.
P411
P412	Do not expose to temperatures exceeding 50 oC/ 122 oF.
P413
P420	Store away from other materials.
P422
P402 + P404	Store in a dry place. Store in a closed container.
P403 + P233	Store in a well-ventilated place. Keep container tightly closed.
P403 + P235	Store in a well-ventilated place. Keep cool.
P410 + P403	Protect from sunlight. Store in a well-ventilated place.
P410 + P412	Protect from sunlight. Do not expose to temperatures exceeding 50 oC/122oF.
P411 + P235	Keep cool.
Disposal
Code	Phrase
P501	Dispose of contents/container to ...
P502	Refer to manufacturer/supplier for information on recovery/recycling

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CAS No.: 2022-85-7

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CAS No.: 2022-85-7

Alternative Products

Product Details of 5-Fluorocytosine

Safety of 5-Fluorocytosine

Isoform Comparison

Biological Activity

Protocol

References

Historical Records

Categories

Precautionary Statements-General

Prevention

Response

Storage

Disposal

Physical hazards

Health hazards

Environmental hazards

Inquiry

Molarity Calculator

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Physical hazards
Code	Phrase
H200	Unstable explosive
H201	Explosive; mass explosion hazard
H202	Explosive; severe projection hazard
H203	Explosive; fire, blast or projection hazard
H204	Fire or projection hazard
H205	May mass explode in fire
H220	Extremely flammable gas
H221	Flammable gas
H222	Extremely flammable aerosol
H223	Flammable aerosol
H224	Extremely flammable liquid and vapour
H225	Highly flammable liquid and vapour
H226	Flammable liquid and vapour
H227	Combustible liquid
H228	Flammable solid
H229	Pressurized container: may burst if heated
H230	May react explosively even in the absence of air
H231	May react explosively even in the absence of air at elevated pressure and/or temperature
H240	Heating may cause an explosion
H241	Heating may cause a fire or explosion
H242	Heating may cause a fire
H250	Catches fire spontaneously if exposed to air
H251	Self-heating; may catch fire
H252	Self-heating in large quantities; may catch fire
H260	In contact with water releases flammable gases which may ignite spontaneously
H261	In contact with water releases flammable gas
H270	May cause or intensify fire; oxidizer
H271	May cause fire or explosion; strong oxidizer
H272	May intensify fire; oxidizer
H280	Contains gas under pressure; may explode if heated
H281	Contains refrigerated gas; may cause cryogenic burns or injury
H290	May be corrosive to metals
Health hazards
Code	Phrase
H300	Fatal if swallowed
H301	Toxic if swallowed
H302	Harmful if swallowed
H303	May be harmful if swallowed