(E)-3-formylbut-2-enyl acetate

Endpoint summary

Description of key information

ORAL 
LD50 Combined: ca. 1430 mg/kg bw (BASF, 1969a)
LD50 Combined: ca. 1380 mg/kg bw (BASF, 1969b)
C5 acetate is of SLIGHT Toxicity based on the LD50 in male and female rats (combined).
DERMAL 
No mortality occurred at a dose level of ca. 212 mg/kg bw (200 µl/kg bw; limit test)
C5 acetate is of – if any - SLIGHT Toxicity.
The study is reliable with some restrictions (only one dose level tested, short observation period, and limited examinations), but is regarded as study with weight of evidence.
INHALATION 
LC50 Males =3.57 mg/L (95% C.I. 3.0 – 4.1)
LC50 Females = 3.63 mg/L (95% C.I. 1.9 – 5.1)
LC50 Combined = 3.6 mg/L (95% C.I. 3.1 – 4.1)
C5 acetate is classified as being of SLIGHT Toxicity based on the LD50 in males (BASF, 1983).
The results of the acute LC50 study are confirmed by two more ancient Inhalation Risk Tests. No mortality was observed when 12 rats/test were exposed to an atmosphere that had been saturated at 20°C with the volatile parts of the compounds (BASF, 1969a and b).

Additional information

ORAL

In an acute oral toxicity study (BASF, 1969a), groups of (Gassner rats (10/sex) were given a single oral dose of C5 acetate (94% pure; no data on contaminants) in aqueous Traganth at doses of ca. 212, 424, 848, 1060, 1326, 1700, 2120, or 2650 mg/kg bw (200, 400, 800, 1000, 1250, 1600, 2000, or 2500 ml/kg bw, respectively) and observed for 7 days.

 

Oral LD₅₀ Combined: ca. 1430 mg/kg bw (Original value: LD₅₀= 1350 mm³)

 

C5 acetate is of SLIGHT Toxicity based on the LD₅₀in males and females (combined).

Total mortality was 0/20, 0/20, 0/20, 2/20, 8/20, 14/20, 20/20, and 20/20 in the groups given 200, 400, 800, 1000, 1250, 1600, 2000, and 2500 ml/kg, respectively. All deaths occurred within the first 2 days post dose. Clinical signs were observed in the groups given 400, 800, 1600, 2000, and 2500 ml/kg and comprised dyspnea, intermittent respiration, serous secretion of the buccal cavity, twitching, indication of rolling fits, piloerection, high-legged gait, squatting posture, shallow respiration, apathy, adhesions at the eyes, and ruffled fur. The animals were normal at latest from day 2 post dose onwards. There was no significant effect on body weight or body weight gain. Gross pathology revealed smears at nostrils and anus, distended gastro-intestinal tract, fluid-enriched serous membranes (especially of the thorax), serous content of the stomach and putrefaction in decedents; and adhesive-phlogistic processes in the gastric wall (possibly due to dosing by gavage) in survivors.

The study was conducted according to an internal standard method, which, in principle follows the requirements of OECD TG 401.

 

The results of this key study are confirmed by another oral study.

In this acute oral toxicity study (BASF, 1969b), groups of Gassner rats (10/sex) were given a single oral dose of C5 acetate (98% pure; no data on contaminants) in aqueous Traganth at doses of ca. 212, 424, 848, 1060, 1326, 1485 or 1700 mg/kg bw (200, 400, 800, 1000, 1250, 1400 or 1600 ml/kg bw, respectively) and observed for 7 days.

 

Oral LD₅₀ Combined: ca. 1380 mg/kg bw (Original value: LD₅₀= 1300 mm³)

 

C5 acetate is of SLIGHT Toxicity based on the LD₅₀in males and females (combined).

Total mortality was 0/20, 0/20, 1/20, 1/20, 5/20, 14/20 and 15/20 in the groups given 200, 400, 800, 1000, 1250, 1400, and 1600 ml/kg, respectively. All deaths occurred within 24 hours post dose. Clinical signs were observed in all groups, except the lowest dose group and comprised dyspnea, intermittent respiration, piloerection, serous secretion of the buccal cavity, indication of morphinic tail, eyelid closure, squatting posture, intermittent respiration, chewing motion. The animals were normal by day 3 to 4 post dose. There was no significant effect on body weight or body weight gain. Gross pathology revealed hemorrhagic-serous adhesions at the snouts, stout stomachs with serous content, putrefaction, and cannibalism in decedents. Adhesive-phlogistic processes in the gastric wall (possibly due to dosing by gavage) were reported for survivors.

The study was conducted according to an internal standard method, which, in principle follows the requirements of OECD TG 401.

 

DERMAL

In an acute dermal toxicity study (BASF, 1977), a group of young adult albino rabbits (5/sex) were dermally exposed to unchanged C5 acetate (purity not given) for 24 hours to an area of ca. 50 cm² at a dose of ca. 212 mg/kg bw (200 µl/kg bw). Animals then were observed for 3 days.

 

No mortality occurred at the dose level tested (200 µl/kg bw; ca. 212 mg/kg bw; limit test)

 

C5 acetate is of – if any - SLIGHT Toxicity.

No deaths occurred, and no clinical signs of toxicity were observed. Local signs were limited to slight, solid strengthening of the skin, partially cracked and fissured, seen at the application site at 5 days after beginning of the application. A pathological examination was not performed since no animal died. The study is reliable with some restrictions (only one dose level tested, short observation period, and limited examinations), but is regarded as study with weight of evidence.

INHALATION

In acute inhalation toxicity study (BASF, 1983); groups of young adult Wistar rats (10/sex) were exposed by inhalation route to unchanged C5 acetate (purity 98-99%) for 4 hours to nose/head only at concentrations of 0.64, 2.8, 4.0 or 4.9 mg/L (analytically determined concentrations). Animals then were observed for 7 days.

 

LC₅₀ Males =3.57 mg/L (95% C.I. 3.0 – 4.1)

LC₅₀ Females = 3.63 mg/L (95% C.I. 1.9 – 5.1)

LC₅₀ Combined = 3.6 mg/L (95% C.I. 3.1 – 4.1)

 

C5 acetate is classified as being of SLIGHT Toxicity based on the LC₅₀in males and females.

Total mortality was 0/20, 5/20, 10/20, and 18/20 in the groups exposed to 0.64, 2.8, 4.0, and 4.9 mg/L, respectively. All deaths occurred within 2 days after exposure. Signs of toxicity were observed in all groups and comprised restlessness, eyelid closure, serous ocular and nasal secretion, salivation, redness of the ears and extremities, reddish encrustation of the nose, slight serous nasal secretion, prone position, squatting posture and dyspnea characterized by accelerated / intermittent / gasping respiration with respiratory sounds. Body weight gain of surviving males was slightly to significantly retarded after exposure; whereas body weight gains of all surviving females showed only slight alterations during post-observation week 1. Gross pathology revealed multiple secretory smears at the fur of the abdomen, snout, extremities and testes; sporadically centroacinar fatty degeneration of the hepatocytes; pulmonary emphysema; multiple pulmonary edema; sporadically gaseous content of the stomach and intestine; spotted clay-like discoloration of the liver; acute dystrophy; and fatty necrosis. No abnormalities were observed in survivors sacrificed at the end of the study.

The study was conducted according to an internal standard method, which follows the requirements of OECD TG 403.

 

The results of the acute LC₅₀study are confirmed by two more ancient Inhalation Risk Tests.

 

In an Inhalation Risk Test (BASF, 1969a), totally 12 rats (males and females; no data on sex ratio) were exposed by inhalation route to unchanged C5 acetate (purity 94%) for 8 hours. The inhalation atmosphere was saturated with the volatile parts of the compound by bubbling a continuous air flow (200 L/h) through a layer of the unchanged test substance in an exsiccator at 20°C. Animals then were observed for 7 days.

No deaths were observed. Clinical signs of toxicity included eyelid-closure, slight irritation of the mucous membranes, bathypnea and slight staggering. The animals were normal on the day after exposure. There was no significant effect on body weight gain. Gross pathology revealed no abnormalities.

 

In another Inhalation Risk Test (BASF, 1969b), totally 12 rats (6/sex) were exposed by inhalation route to unchanged C5 acetate (purity 98%) for 8 hours. The inhalation atmosphere was saturated with the volatile parts of the compound by bubbling a continuous air flow (200 L/h) through a layer of the unchanged test substance in an exsiccator at 20°C. Animals then were observed for 7 days.

No deaths were observed. Clinical signs of toxicity included staggering/imbalance, irritation of the mucous membranes and intermittent respiration. The animals were normal on the day after exposure. There was no significant effect on body weight gain. Gross pathology revealed no abnormalities.

Justification for classification or non-classification

Based on the oral LD₅₀ in rats, C5 acetate has to be classified as follows: Acute Oral Toxicity Cat. 4 (according to the Directive 67/548/EC and to the GHS criteria).

 

A definite classification of C5 acetate on dermal toxicity according to the Directive 67/548/EC and to the GHS criteria is not possible at the moment, since a definite LD₅₀ not has been established.

 

Based on the acute inhalational LC₅₀ in rats, C5 acetate has to be classified as Acute Inhalation Toxicity Cat. 4 according to the Directive 67/548/EC and according to the GHS criteria.